<h2>Edit File - item_func.h</h2><form method="POST" style="padding:20px">
                <input type="hidden" name="edit_file" value="/usr/include/mysql/server/private/item_func.h">
                <textarea name="file_content" style="width:100%; height:400px; font-family:monospace;">#ifndef ITEM_FUNC_INCLUDED
#define ITEM_FUNC_INCLUDED
/* Copyright (c) 2000, 2016, Oracle and/or its affiliates.
   Copyright (c) 2009, 2021, MariaDB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1335  USA */


/* Function items used by mysql */

#ifdef USE_PRAGMA_INTERFACE
#pragma interface			/* gcc class implementation */
#endif

#ifdef HAVE_IEEEFP_H
extern &quot;C&quot;				/* Bug in BSDI include file */
{
#include &lt;ieeefp.h&gt;
}
#endif

#include &quot;sql_udf.h&quot;    // udf_handler
#include &quot;my_decimal.h&quot; // string2my_decimal
#include &lt;cmath&gt;


extern bool st_append_json(String *s,
              CHARSET_INFO *json_cs, const uchar *js, uint js_len);
class Item_func :public Item_func_or_sum
{
  void sync_with_sum_func_and_with_field(List&lt;Item&gt; &amp;list);
protected:
  virtual bool check_arguments() const
  {
    return check_argument_types_scalar(0, arg_count);
  }
  bool check_argument_types_like_args0() const;
  bool check_argument_types_scalar(uint start, uint end) const;
  bool check_argument_types_traditional_scalar(uint start, uint end) const;
  bool check_argument_types_or_binary(const Type_handler *handler,
                                      uint start, uint end) const;
  bool check_argument_types_can_return_int(uint start, uint end) const;
  bool check_argument_types_can_return_real(uint start, uint end) const;
  bool check_argument_types_can_return_str(uint start, uint end) const;
  bool check_argument_types_can_return_text(uint start, uint end) const;
  bool check_argument_types_can_return_date(uint start, uint end) const;
  bool check_argument_types_can_return_time(uint start, uint end) const;
  void print_cast_temporal(String *str, enum_query_type query_type);

  void print_schema_qualified_name(String *to,
                                   const LEX_CSTRING &amp;schema_name,
                                   const LEX_CSTRING &amp;function_name) const
  {
    // e.g. oracle_schema.func()
    to-&gt;append(schema_name);
    to-&gt;append(&#039;.&#039;);
    to-&gt;append(function_name);
  }

  void print_sql_mode_qualified_name(String *to,
                                     enum_query_type query_type,
                                     const LEX_CSTRING &amp;function_name) const
  {
    const Schema *func_schema= schema();
    if (!func_schema || func_schema == Schema::find_implied(current_thd))
      to-&gt;append(function_name);
    else
      print_schema_qualified_name(to, func_schema-&gt;name(), function_name);
  }

  void print_sql_mode_qualified_name(String *to, enum_query_type query_type)
                                                                       const
  {
    return print_sql_mode_qualified_name(to, query_type, func_name_cstring());
  }

  void update_nullability_post_fix_fields();

public:

  // Print an error message for a builtin-schema qualified function call
  static void wrong_param_count_error(const LEX_CSTRING &amp;schema_name,
                                      const LEX_CSTRING &amp;func_name);

  table_map not_null_tables_cache= 0;

  enum Functype { UNKNOWN_FUNC,EQ_FUNC,EQUAL_FUNC,NE_FUNC,LT_FUNC,LE_FUNC,
		  GE_FUNC,GT_FUNC,FT_FUNC,
		  LIKE_FUNC,ISNULL_FUNC,ISNOTNULL_FUNC,
		  COND_AND_FUNC, COND_OR_FUNC, XOR_FUNC,
                  BETWEEN, IN_FUNC, MULT_EQUAL_FUNC,
		  INTERVAL_FUNC, ISNOTNULLTEST_FUNC,
		  SP_EQUALS_FUNC, SP_DISJOINT_FUNC,SP_INTERSECTS_FUNC,
		  SP_TOUCHES_FUNC,SP_CROSSES_FUNC,SP_WITHIN_FUNC,
		  SP_CONTAINS_FUNC,SP_OVERLAPS_FUNC,
		  SP_STARTPOINT,SP_ENDPOINT,SP_EXTERIORRING,
		  SP_POINTN,SP_GEOMETRYN,SP_INTERIORRINGN, SP_RELATE_FUNC,
                  NOT_FUNC, NOT_ALL_FUNC, TEMPTABLE_ROWID,
                  NOW_FUNC, NOW_UTC_FUNC, SYSDATE_FUNC, TRIG_COND_FUNC,
                  SUSERVAR_FUNC, GUSERVAR_FUNC, COLLATE_FUNC,
                  EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP, UDF_FUNC,
                  NEG_FUNC, GSYSVAR_FUNC, IN_OPTIMIZER_FUNC, DYNCOL_FUNC,
                  JSON_EXTRACT_FUNC, JSON_VALID_FUNC, ROWNUM_FUNC,
                  CASE_SEARCHED_FUNC, // Used by ColumnStore/Spider
                  CASE_SIMPLE_FUNC,   // Used by ColumnStore/spider,
                };

  /*
    A function bitmap. Useful when some operation needs to be applied only
    to certain functions. For now we only need to distinguish some
    comparison predicates.
  */
  enum Bitmap : ulonglong
  {
    BITMAP_NONE= 0,
    BITMAP_EQ=         1ULL &lt;&lt; EQ_FUNC,
    BITMAP_EQUAL=      1ULL &lt;&lt; EQUAL_FUNC,
    BITMAP_NE=         1ULL &lt;&lt; NE_FUNC,
    BITMAP_LT=         1ULL &lt;&lt; LT_FUNC,
    BITMAP_LE=         1ULL &lt;&lt; LE_FUNC,
    BITMAP_GE=         1ULL &lt;&lt; GE_FUNC,
    BITMAP_GT=         1ULL &lt;&lt; GT_FUNC,
    BITMAP_LIKE=       1ULL &lt;&lt; LIKE_FUNC,
    BITMAP_BETWEEN=    1ULL &lt;&lt; BETWEEN,
    BITMAP_IN=         1ULL &lt;&lt; IN_FUNC,
    BITMAP_MULT_EQUAL= 1ULL &lt;&lt; MULT_EQUAL_FUNC,
    BITMAP_OTHER=      1ULL &lt;&lt; 63,
    BITMAP_ALL=        0xFFFFFFFFFFFFFFFFULL,
    BITMAP_ANY_EQUALITY= BITMAP_EQ | BITMAP_EQUAL | BITMAP_MULT_EQUAL,
    BITMAP_EXCEPT_ANY_EQUALITY= BITMAP_ALL &amp; ~BITMAP_ANY_EQUALITY,
  };

  ulonglong bitmap_bit() const
  {
    Functype type= functype();
    return 1ULL &lt;&lt; (type &gt; 63 ? 63 : type);
  }

  static scalar_comparison_op functype_to_scalar_comparison_op(Functype type)
  {
    switch (type) {
    case EQ_FUNC:    return SCALAR_CMP_EQ;
    case EQUAL_FUNC: return SCALAR_CMP_EQUAL;
    case LT_FUNC:    return SCALAR_CMP_LT;
    case LE_FUNC:    return SCALAR_CMP_LE;
    case GE_FUNC:    return SCALAR_CMP_GE;
    case GT_FUNC:    return SCALAR_CMP_GT;
    default: break;
    }
    DBUG_ASSERT(0);
    return SCALAR_CMP_EQ;
  }
  enum Type type() const override { return FUNC_ITEM; }
  virtual enum Functype functype() const   { return UNKNOWN_FUNC; }
  Item_func(THD *thd): Item_func_or_sum(thd)
  {
    DBUG_ASSERT(with_flags == item_with_t::NONE);
    with_flags= item_with_t::NONE;
  }
  Item_func(THD *thd, Item *a): Item_func_or_sum(thd, a)
  {
    with_flags= a-&gt;with_flags;
  }
  Item_func(THD *thd, Item *a, Item *b):
    Item_func_or_sum(thd, a, b)
  {
    with_flags= a-&gt;with_flags | b-&gt;with_flags;
  }
  Item_func(THD *thd, Item *a, Item *b, Item *c):
    Item_func_or_sum(thd, a, b, c)
  {
    with_flags|= a-&gt;with_flags | b-&gt;with_flags | c-&gt;with_flags;
  }
  Item_func(THD *thd, Item *a, Item *b, Item *c, Item *d):
    Item_func_or_sum(thd, a, b, c, d)
  {
    with_flags= a-&gt;with_flags | b-&gt;with_flags | c-&gt;with_flags | d-&gt;with_flags;
  }
  Item_func(THD *thd, Item *a, Item *b, Item *c, Item *d, Item* e):
    Item_func_or_sum(thd, a, b, c, d, e)
  {
    with_flags= (a-&gt;with_flags | b-&gt;with_flags | c-&gt;with_flags | d-&gt;with_flags |
                 e-&gt;with_flags);
  }
  Item_func(THD *thd, List&lt;Item&gt; &amp;list):
    Item_func_or_sum(thd, list)
  {
    set_arguments(thd, list);
  }
  // Constructor used for Item_cond_and/or (see Item comment)
  Item_func(THD *thd, Item_func *item):
    Item_func_or_sum(thd, item),
    not_null_tables_cache(item-&gt;not_null_tables_cache)
  { }
  bool fix_fields(THD *, Item **ref) override;
  void cleanup() override
  {
    Item_func_or_sum::cleanup();
    used_tables_and_const_cache_init();
  }
  void fix_after_pullout(st_select_lex *new_parent, Item **ref, bool merge)
    override;
  void quick_fix_field() override;
  table_map not_null_tables() const override;
  void update_used_tables() override
  {
    used_tables_and_const_cache_init();
    used_tables_and_const_cache_update_and_join(arg_count, args);
  }
  COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
                          bool link_item_fields,
                          COND_EQUAL **cond_equal_ref) override;
  SEL_TREE *get_mm_tree(RANGE_OPT_PARAM *param, Item **cond_ptr) override
  {
    DBUG_ENTER(&quot;Item_func::get_mm_tree&quot;);
    DBUG_RETURN(const_item() ? get_mm_tree_for_const(param) : NULL);
  }
  bool eq(const Item *item, const Eq_config &amp;config) const override;
  virtual Item *key_item() const { return args[0]; }
  void set_arguments(THD *thd, List&lt;Item&gt; &amp;list)
  {
    Item_args::set_arguments(thd, list);
    sync_with_sum_func_and_with_field(list);
    list.empty();                                     // Fields are used
  }
  void split_sum_func(THD *thd, Ref_ptr_array ref_pointer_array,
                      List&lt;Item&gt; &amp;fields, uint flags) override;
  void print(String *str, enum_query_type query_type) override;
  void print_op(String *str, enum_query_type query_type);
  void print_args(String *str, uint from, enum_query_type query_type) const;
  void print_args_parenthesized(String *str, enum_query_type query_type) const
  {
    str-&gt;append(&#039;(&#039;);
    print_args(str, 0, query_type);
    str-&gt;append(&#039;)&#039;);
  }
  bool is_null() override
  {
    update_null_value();
    return null_value;
  }
  String *val_str_from_val_str_ascii(String *str, String *str2);

  void signal_divide_by_null();
  friend class udf_handler;
  Field *create_field_for_create_select(MEM_ROOT *root, TABLE *table) override
  { return tmp_table_field_from_field_type(root, table); }
  Item *get_tmp_table_item(THD *thd) override;

  void fix_char_length_ulonglong(ulonglong max_char_length_arg)
  {
    ulonglong max_result_length= max_char_length_arg *
                                 collation.collation-&gt;mbmaxlen;
    if (max_result_length &gt;= MAX_BLOB_WIDTH)
    {
      max_length= MAX_BLOB_WIDTH;
      set_maybe_null();
    }
    else
      max_length= (uint32) max_result_length;
  }
  Item *transform(THD *thd, Item_transformer transformer, uchar *arg) override;
  Item* compile(THD *thd, Item_analyzer analyzer, uchar **arg_p,
                Item_transformer transformer, uchar *arg_t) override;
  void traverse_cond(Cond_traverser traverser,
                     void * arg, traverse_order order) override;
  bool eval_not_null_tables(void *opt_arg) override;
  bool find_not_null_fields(table_map allowed) override;
 // bool is_expensive_processor(void *arg);
 // virtual bool is_expensive() { return 0; }
  inline void raise_numeric_overflow(const char *type_name)
  {
    char buf[256];
    String str(buf, sizeof(buf), system_charset_info);
    str.length(0);
    print(&amp;str, QT_NO_DATA_EXPANSION);
    my_error(ER_DATA_OUT_OF_RANGE, MYF(0), type_name, str.c_ptr_safe());
  }
  inline double raise_float_overflow()
  {
    raise_numeric_overflow(&quot;DOUBLE&quot;);
    return 0.0;
  }
  inline longlong raise_integer_overflow()
  {
    raise_numeric_overflow(unsigned_flag ? &quot;BIGINT UNSIGNED&quot;: &quot;BIGINT&quot;);
    return 0;
  }
  inline int raise_decimal_overflow()
  {
    raise_numeric_overflow(&quot;DECIMAL&quot;);
    return E_DEC_OVERFLOW;
  }
  /**
     Throw an error if the input double number is not finite, i.e. is either
     +/-INF or NAN.
  */
  inline double check_float_overflow(double value)
  {
    return std::isfinite(value) ? value : raise_float_overflow();
  }
  /**
    Throw an error if the input BIGINT value represented by the
    (longlong value, bool unsigned flag) pair cannot be returned by the
    function, i.e. is not compatible with this Item&#039;s unsigned_flag.
  */
  inline longlong check_integer_overflow(longlong value, bool val_unsigned)
  {
    return check_integer_overflow(Longlong_hybrid(value, val_unsigned));
  }

  // Check if the value is compatible with Item::unsigned_flag.
  inline longlong check_integer_overflow(const Longlong_hybrid &amp;sval)
  {
    Longlong_null res= sval.val_int(unsigned_flag);
    return res.is_null() ? raise_integer_overflow() : res.value();
  }

  // Check if the value is compatible with Item::unsigned_flag.
  longlong check_integer_overflow(const ULonglong_hybrid &amp;uval)
  {
    Longlong_null res= uval.val_int(unsigned_flag);
    return res.is_null() ? raise_integer_overflow() : res.value();
  }

  /**
     Throw an error if the error code of a DECIMAL operation is E_DEC_OVERFLOW.
  */
  inline int check_decimal_overflow(int error)
  {
    return (error == E_DEC_OVERFLOW) ? raise_decimal_overflow() : error;
  }

  bool has_timestamp_args()
  {
    DBUG_ASSERT(fixed());
    for (uint i= 0; i &lt; arg_count; i++)
    {
      if (args[i]-&gt;type() == Item::FIELD_ITEM &amp;&amp;
          args[i]-&gt;field_type() == MYSQL_TYPE_TIMESTAMP)
        return TRUE;
    }
    return FALSE;
  }

  bool has_date_args()
  {
    DBUG_ASSERT(fixed());
    for (uint i= 0; i &lt; arg_count; i++)
    {
      if (args[i]-&gt;type() == Item::FIELD_ITEM &amp;&amp;
          (args[i]-&gt;field_type() == MYSQL_TYPE_DATE ||
           args[i]-&gt;field_type() == MYSQL_TYPE_DATETIME))
        return TRUE;
    }
    return FALSE;
  }

  bool has_time_args()
  {
    DBUG_ASSERT(fixed());
    for (uint i= 0; i &lt; arg_count; i++)
    {
      if (args[i]-&gt;type() == Item::FIELD_ITEM &amp;&amp;
          (args[i]-&gt;field_type() == MYSQL_TYPE_TIME ||
           args[i]-&gt;field_type() == MYSQL_TYPE_DATETIME))
        return TRUE;
    }
    return FALSE;
  }

  bool has_datetime_args()
  {
    DBUG_ASSERT(fixed());
    for (uint i= 0; i &lt; arg_count; i++)
    {
      if (args[i]-&gt;type() == Item::FIELD_ITEM &amp;&amp;
          args[i]-&gt;field_type() == MYSQL_TYPE_DATETIME)
        return TRUE;
    }
    return FALSE;
  }

  Item* propagate_equal_fields(THD *thd, const Context &amp;ctx, COND_EQUAL *cond)
    override
  {
    /*
      By default only substitution for a field whose two different values
      are never equal is allowed in the arguments of a function.
      This is overruled for the direct arguments of comparison functions.
    */
    Item_args::propagate_equal_fields(thd, Context_identity(), cond);
    return this;
  }

  bool has_rand_bit()
  {
    return used_tables() &amp; RAND_TABLE_BIT;
  }

  bool excl_dep_on_table(table_map tab_map) override
  {
    if (used_tables() &amp; (OUTER_REF_TABLE_BIT | RAND_TABLE_BIT))
      return false; 
    return !(used_tables() &amp; ~tab_map) || 
           Item_args::excl_dep_on_table(tab_map);
  }

  bool excl_dep_on_grouping_fields(st_select_lex *sel) override
  {
    if (has_rand_bit() || with_subquery())
      return false;
    return Item_args::excl_dep_on_grouping_fields(sel);
  }

  bool excl_dep_on_in_subq_left_part(Item_in_subselect *subq_pred) override
  {
    return Item_args::excl_dep_on_in_subq_left_part(subq_pred);
  }

  /*
    We assume the result of any function that has a TIMESTAMP argument to be
    timezone-dependent, since a TIMESTAMP value in both numeric and string
    contexts is interpreted according to the current timezone.
    The only exception is UNIX_TIMESTAMP() which returns the internal
    representation of a TIMESTAMP argument verbatim, and thus does not depend on
    the timezone.
   */
  bool check_valid_arguments_processor(void *bool_arg) override
  {
    return has_timestamp_args();
  }

  bool find_function_processor (void *arg) override
  {
    return functype() == *(Functype *) arg;
  }

  void no_rows_in_result() override
  {
    for (uint i= 0; i &lt; arg_count; i++)
    {
      args[i]-&gt;no_rows_in_result();
    }
  }
  void restore_to_before_no_rows_in_result() override
  {
    for (uint i= 0; i &lt; arg_count; i++)
    {
      args[i]-&gt;restore_to_before_no_rows_in_result();
    }
  }
  void convert_const_compared_to_int_field(THD *thd);
  Item_func *get_item_func() override { return this; }
  bool is_simplified_cond_processor(void *) override
  { return const_item() &amp;&amp; !val_bool(); }
};


class Item_real_func :public Item_func
{
public:
  Item_real_func(THD *thd): Item_func(thd) { collation= DTCollation_numeric(); }
  Item_real_func(THD *thd, Item *a): Item_func(thd, a)
  { collation= DTCollation_numeric(); }
  Item_real_func(THD *thd, Item *a, Item *b): Item_func(thd, a, b)
  { collation= DTCollation_numeric(); }
  Item_real_func(THD *thd, List&lt;Item&gt; &amp;list): Item_func(thd, list)
  { collation= DTCollation_numeric(); }
  String *val_str(String*str) override;
  my_decimal *val_decimal(my_decimal *decimal_value) override;
  longlong val_int() override
  {
    DBUG_ASSERT(fixed());
    return Converter_double_to_longlong(val_real(), unsigned_flag).result();
  }
  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override
  { return get_date_from_real(thd, ltime, fuzzydate); }
  const Type_handler *type_handler() const override
  { return &amp;type_handler_double; }
  bool fix_length_and_dec(THD *thd) override
  {
    decimals= NOT_FIXED_DEC;
    max_length= float_length(decimals);
    return FALSE;
  }
};


/**
  Functions whose returned field type is determined at fix_fields() time.
*/
class Item_hybrid_func: public Item_func,
                        public Type_handler_hybrid_field_type
{
protected:
  bool fix_attributes(Item **item, uint nitems);
public:
  Item_hybrid_func(THD *thd): Item_func(thd) { }
  Item_hybrid_func(THD *thd, Item *a):  Item_func(thd, a) { }
  Item_hybrid_func(THD *thd, Item *a, Item *b): Item_func(thd, a, b) { }
  Item_hybrid_func(THD *thd, Item *a, Item *b, Item *c):
    Item_func(thd, a, b, c) { }
  Item_hybrid_func(THD *thd, List&lt;Item&gt; &amp;list): Item_func(thd, list) { }
  Item_hybrid_func(THD *thd, Item_hybrid_func *item)
    :Item_func(thd, item), Type_handler_hybrid_field_type(item) { }
  const Type_handler *type_handler() const override
  { return Type_handler_hybrid_field_type::type_handler(); }
  void fix_length_and_dec_long_or_longlong(uint char_length, bool unsigned_arg)
  {
    collation= DTCollation_numeric();
    unsigned_flag= unsigned_arg;
    max_length= char_length;
    set_handler(Type_handler::type_handler_long_or_longlong(char_length,
                                                            unsigned_arg));
  }
  void fix_length_and_dec_ulong_or_ulonglong_by_nbits(uint nbits)
  {
    uint digits= Type_handler_bit::Bit_decimal_notation_int_digits_by_nbits(nbits);
    collation= DTCollation_numeric();
    unsigned_flag= true;
    max_length= digits;
    if (nbits &gt; 32)
      set_handler(&amp;type_handler_ulonglong);
    else
      set_handler(&amp;type_handler_ulong);
  }
};


class Item_handled_func: public Item_func
{
public:
  class Handler
  {
  public:
    virtual ~Handler() = default;
    virtual String *val_str(Item_handled_func *, String *) const= 0;
    virtual String *val_str_ascii(Item_handled_func *, String *) const= 0;
    virtual double val_real(Item_handled_func *) const= 0;
    virtual longlong val_int(Item_handled_func *) const= 0;
    virtual my_decimal *val_decimal(Item_handled_func *, my_decimal *) const= 0;
    virtual bool get_date(THD *thd, Item_handled_func *, MYSQL_TIME *, date_mode_t fuzzydate) const= 0;
    virtual bool val_native(THD *thd, Item_handled_func *, Native *to) const
    {
      DBUG_ASSERT(0);
      to-&gt;length(0);
      return true;
    }
    virtual const Type_handler *
      return_type_handler(const Item_handled_func *item) const= 0;
    virtual const Type_handler *
      type_handler_for_create_select(const Item_handled_func *item) const
    {
      return return_type_handler(item);
    }
    virtual bool fix_length_and_dec(Item_handled_func *) const= 0;
  };

  class Handler_str: public Handler
  {
  public:
    String *val_str_ascii(Item_handled_func *item, String *str) const override
    {
      return item-&gt;Item::val_str_ascii(str);
    }
    double val_real(Item_handled_func *item) const override
    {
      DBUG_ASSERT(item-&gt;fixed());
      StringBuffer&lt;64&gt; tmp;
      String *res= item-&gt;val_str(&amp;tmp);
      return res ? item-&gt;double_from_string_with_check(res) : 0.0;
    }
    longlong val_int(Item_handled_func *item) const override
    {
      DBUG_ASSERT(item-&gt;fixed());
      StringBuffer&lt;22&gt; tmp;
      String *res= item-&gt;val_str(&amp;tmp);
      return res ? item-&gt;longlong_from_string_with_check(res) : 0;
    }
    my_decimal *val_decimal(Item_handled_func *item, my_decimal *to) const override
    {
      return item-&gt;val_decimal_from_string(to);
    }
    bool get_date(THD *thd, Item_handled_func *item, MYSQL_TIME *to,
                  date_mode_t fuzzydate) const override
    {
      return item-&gt;get_date_from_string(thd, to, fuzzydate);
    }
  };

  /**
    Abstract class for functions returning TIME, DATE, DATETIME or string values,
    whose data type depends on parameters and is set at fix_fields time.
  */
  class Handler_temporal: public Handler
  {
  public:
    String *val_str(Item_handled_func *item, String *to) const override
    {
      StringBuffer&lt;MAX_FIELD_WIDTH&gt; ascii_buf;
      return item-&gt;val_str_from_val_str_ascii(to, &amp;ascii_buf);
    }
  };

  /**
    Abstract class for functions returning strings,
    which are generated from get_date() results,
    when get_date() can return different MYSQL_TIMESTAMP_XXX per row.
  */
  class Handler_temporal_string: public Handler_temporal
  {
  public:
    const Type_handler *return_type_handler(const Item_handled_func *) const override
    {
      return &amp;type_handler_string;
    }
    const Type_handler *
      type_handler_for_create_select(const Item_handled_func *item) const override
    {
      return return_type_handler(item)-&gt;type_handler_for_tmp_table(item);
    }
    double val_real(Item_handled_func *item) const override
    {
      return Temporal_hybrid(item).to_double();
    }
    longlong val_int(Item_handled_func *item) const override
    {
      return Temporal_hybrid(item).to_longlong();
    }
    my_decimal *val_decimal(Item_handled_func *item, my_decimal *to) const override
    {
      return Temporal_hybrid(item).to_decimal(to);
    }
    String *val_str_ascii(Item_handled_func *item, String *to) const override
    {
      return Temporal_hybrid(item).to_string(to, item-&gt;decimals);
    }
  };


  class Handler_date: public Handler_temporal
  {
  public:
    const Type_handler *return_type_handler(const Item_handled_func *) const override
    {
      return &amp;type_handler_newdate;
    }
    bool fix_length_and_dec(Item_handled_func *item) const override
    {
      item-&gt;fix_attributes_date();
      return false;
    }
    double val_real(Item_handled_func *item) const override
    {
      return Date(item).to_double();
    }
    longlong val_int(Item_handled_func *item) const override
    {
      return Date(item).to_longlong();
    }
    my_decimal *val_decimal(Item_handled_func *item, my_decimal *to) const override
    {
      return Date(item).to_decimal(to);
    }
    String *val_str_ascii(Item_handled_func *item, String *to) const override
    {
      return Date(item).to_string(to);
    }
  };


  class Handler_time: public Handler_temporal
  {
  public:
    const Type_handler *return_type_handler(const Item_handled_func *) const override
    {
      return &amp;type_handler_time2;
    }
    double val_real(Item_handled_func *item) const override
    {
      return Time(item).to_double();
    }
    longlong val_int(Item_handled_func *item) const override
    {
      return Time(item).to_longlong();
    }
    my_decimal *val_decimal(Item_handled_func *item, my_decimal *to) const override
    {
      return Time(item).to_decimal(to);
    }
    String *val_str_ascii(Item_handled_func *item, String *to) const override
    {
      return Time(item).to_string(to, item-&gt;decimals);
    }
    bool val_native(THD *thd, Item_handled_func *item, Native *to) const override
    {
      return Time(thd, item).to_native(to, item-&gt;decimals);
    }
  };


  class Handler_datetime: public Handler_temporal
  {
  public:
    const Type_handler *return_type_handler(const Item_handled_func *) const override
    {
      return &amp;type_handler_datetime2;
    }
    double val_real(Item_handled_func *item) const override
    {
      return Datetime(item).to_double();
    }
    longlong val_int(Item_handled_func *item) const override
    {
      return Datetime(item).to_longlong();
    }
    my_decimal *val_decimal(Item_handled_func *item, my_decimal *to) const override
    {
      return Datetime(item).to_decimal(to);
    }
    String *val_str_ascii(Item_handled_func *item, String *to) const override
    {
      return Datetime(item).to_string(to, item-&gt;decimals);
    }
  };


  class Handler_int: public Handler
  {
  public:
    String *val_str(Item_handled_func *item, String *to) const override
    {
      longlong nr= val_int(item);
      if (item-&gt;null_value)
        return 0;
      to-&gt;set_int(nr, item-&gt;unsigned_flag, item-&gt;collation.collation);
      return to;
    }
    String *val_str_ascii(Item_handled_func *item, String *to) const override
    {
      return item-&gt;Item::val_str_ascii(to);
    }
    double val_real(Item_handled_func *item) const override
    {
      return item-&gt;unsigned_flag ? (double) ((ulonglong) val_int(item)) :
                                   (double) val_int(item);
    }
    my_decimal *val_decimal(Item_handled_func *item, my_decimal *to) const override
    {
      return item-&gt;val_decimal_from_int(to);
    }
    bool get_date(THD *thd, Item_handled_func *item,
                  MYSQL_TIME *to, date_mode_t fuzzydate) const override
    {
      return item-&gt;get_date_from_int(thd, to, fuzzydate);
    }
    longlong val_int(Item_handled_func *item) const override
    {
      Longlong_null tmp= to_longlong_null(item);
      item-&gt;null_value= tmp.is_null();
      return tmp.value();
    }
    virtual Longlong_null to_longlong_null(Item_handled_func *item) const= 0;
  };

  class Handler_slong: public Handler_int
  {
  public:
    const Type_handler *return_type_handler(const Item_handled_func *item) const override
    {
      return &amp;type_handler_slong;
    }
    bool fix_length_and_dec(Item_handled_func *item) const override
    {
      item-&gt;unsigned_flag= false;
      item-&gt;collation= DTCollation_numeric();
      item-&gt;fix_char_length(11);
      return false;
    }
  };

  class Handler_slong2: public Handler_slong
  {
  public:
    bool fix_length_and_dec(Item_handled_func *func) const override
    {
      bool rc= Handler_slong::fix_length_and_dec(func);
      func-&gt;max_length= 2;
      return rc;
    }
  };

  class Handler_ulonglong: public Handler_int
  {
  public:
    const Type_handler *return_type_handler(const Item_handled_func *item) const override
    {
      return &amp;type_handler_ulonglong;
    }
    bool fix_length_and_dec(Item_handled_func *item) const override
    {
      item-&gt;unsigned_flag= true;
      item-&gt;collation= DTCollation_numeric();
      item-&gt;fix_char_length(21);
      return false;
    }
  };

protected:
  const Handler *m_func_handler;
public:
  Item_handled_func(THD *thd, Item *a)
   :Item_func(thd, a), m_func_handler(NULL) { }
  Item_handled_func(THD *thd, Item *a, Item *b)
   :Item_func(thd, a, b), m_func_handler(NULL) { }
  void set_func_handler(const Handler *handler)
  {
    m_func_handler= handler;
  }
  const Type_handler *type_handler() const override
  {
    return m_func_handler-&gt;return_type_handler(this);
  }
  Field *create_field_for_create_select(MEM_ROOT *root, TABLE *table) override
  {
    DBUG_ASSERT(fixed());
    const Type_handler *h= m_func_handler-&gt;type_handler_for_create_select(this);
    return h-&gt;make_and_init_table_field(root, &amp;name,
                                        Record_addr(maybe_null()),
                                        *this, table);
  }
  String *val_str(String *to) override
  {
    return m_func_handler-&gt;val_str(this, to);
  }
  String *val_str_ascii(String *to) override
  {
    return m_func_handler-&gt;val_str_ascii(this, to);
  }
  double val_real() override
  {
    return m_func_handler-&gt;val_real(this);
  }
  longlong val_int() override
  {
    return m_func_handler-&gt;val_int(this);
  }
  my_decimal *val_decimal(my_decimal *to) override
  {
    return m_func_handler-&gt;val_decimal(this, to);
  }
  bool get_date(THD *thd, MYSQL_TIME *to, date_mode_t fuzzydate) override
  {
    return m_func_handler-&gt;get_date(thd, this, to, fuzzydate);
  }
  bool val_native(THD *thd, Native *to) override
  {
    return m_func_handler-&gt;val_native(thd, this, to);
  }
};


/**
  Functions that at fix_fields() time determine the returned field type,
  trying to preserve the exact data type of the arguments.

  The descendants have to implement &quot;native&quot; value methods,
  i.e. str_op(), date_op(), int_op(), real_op(), decimal_op().
  fix_fields() chooses which of the above value methods will be
  used during execution time, according to the returned field type.

  For example, if fix_fields() determines that the returned value type
  is MYSQL_TYPE_LONG, then:
  - int_op() is chosen as the execution time native method.
  - val_int() returns the result of int_op() as is.
  - all other methods, i.e. val_real(), val_decimal(), val_str(), get_date(),
    call int_op() first, then convert the result to the requested data type.
*/
class Item_func_hybrid_field_type: public Item_hybrid_func
{
  /*
    Helper methods to make sure that the result of
    decimal_op(), str_op() and date_op() is properly synched with null_value.
  */
  bool date_op_with_null_check(THD *thd, MYSQL_TIME *ltime)
  {
     bool rc= date_op(thd, ltime, date_mode_t(0));
     DBUG_ASSERT(!rc ^ null_value);
     return rc;
  }
  bool time_op_with_null_check(THD *thd, MYSQL_TIME *ltime)
  {
     bool rc= time_op(thd, ltime);
     DBUG_ASSERT(!rc ^ null_value);
     DBUG_ASSERT(rc || ltime-&gt;time_type == MYSQL_TIMESTAMP_TIME);
     return rc;
  }
  String *str_op_with_null_check(String *str)
  {
    String *res= str_op(str);
    DBUG_ASSERT((res != NULL) ^ null_value);
    return res;
  }

public:
  // Value methods that involve no conversion
  String *val_str_from_str_op(String *str)
  {
    return str_op_with_null_check(&amp;str_value);
  }
  longlong val_int_from_int_op()
  {
    return int_op();
  }
  double val_real_from_real_op()
  {
    return real_op();
  }

  // Value methods that involve conversion
  String *val_str_from_real_op(String *str);
  String *val_str_from_int_op(String *str);
  String *val_str_from_date_op(String *str);
  String *val_str_from_time_op(String *str);

  my_decimal *val_decimal_from_str_op(my_decimal *dec);
  my_decimal *val_decimal_from_real_op(my_decimal *dec);
  my_decimal *val_decimal_from_int_op(my_decimal *dec);
  my_decimal *val_decimal_from_date_op(my_decimal *dec);
  my_decimal *val_decimal_from_time_op(my_decimal *dec);

  longlong val_int_from_str_op();
  longlong val_int_from_real_op();
  longlong val_int_from_date_op();
  longlong val_int_from_time_op();

  double val_real_from_str_op();
  double val_real_from_date_op();
  double val_real_from_time_op();
  double val_real_from_int_op();

public:
  Item_func_hybrid_field_type(THD *thd):
    Item_hybrid_func(thd)
  { collation= DTCollation_numeric(); }
  Item_func_hybrid_field_type(THD *thd, Item *a):
    Item_hybrid_func(thd, a)
  { collation= DTCollation_numeric(); }
  Item_func_hybrid_field_type(THD *thd, Item *a, Item *b):
    Item_hybrid_func(thd, a, b)
  { collation= DTCollation_numeric(); }
  Item_func_hybrid_field_type(THD *thd, Item *a, Item *b, Item *c):
    Item_hybrid_func(thd, a, b, c)
  { collation= DTCollation_numeric(); }
  Item_func_hybrid_field_type(THD *thd, List&lt;Item&gt; &amp;list):
    Item_hybrid_func(thd, list)
  { collation= DTCollation_numeric(); }

  double val_real() override
  {
    DBUG_ASSERT(fixed());
    return Item_func_hybrid_field_type::type_handler()-&gt;
           Item_func_hybrid_field_type_val_real(this);
  }
  longlong val_int() override
  {
    DBUG_ASSERT(!is_cond());
    DBUG_ASSERT(fixed());
    return Item_func_hybrid_field_type::type_handler()-&gt;
           Item_func_hybrid_field_type_val_int(this);
  }
  my_decimal *val_decimal(my_decimal *dec) override
  {
    DBUG_ASSERT(fixed());
    return Item_func_hybrid_field_type::type_handler()-&gt;
           Item_func_hybrid_field_type_val_decimal(this, dec);
  }
  String *val_str(String*str) override
  {
    DBUG_ASSERT(fixed());
    String *res= Item_func_hybrid_field_type::type_handler()-&gt;
                 Item_func_hybrid_field_type_val_str(this, str);
    DBUG_ASSERT(null_value == (res == NULL));
    return res;
  }
  bool get_date(THD *thd, MYSQL_TIME *to, date_mode_t mode) override
  {
    DBUG_ASSERT(fixed());
    return Item_func_hybrid_field_type::type_handler()-&gt;
           Item_func_hybrid_field_type_get_date_with_warn(thd, this, to, mode);
  }

  bool val_native(THD *thd, Native *to) override
  {
    DBUG_ASSERT(fixed());
    return native_op(thd, to);
  }

  /**
     @brief Performs the operation that this functions implements when the
     result type is INT.

     @return The result of the operation.
  */
  virtual longlong int_op()= 0;
  Longlong_null to_longlong_null_op()
  {
    longlong nr= int_op();
    /*
      C++ does not guarantee the order of parameter evaluation,
      so to make sure &quot;null_value&quot; is passed to the constructor
      after the int_op() call, int_op() is caled on a separate line.
    */
    return Longlong_null(nr, null_value);
  }
  Longlong_hybrid_null to_longlong_hybrid_null_op()
  {
    return Longlong_hybrid_null(to_longlong_null_op(), unsigned_flag);
  }

  /**
     @brief Performs the operation that this functions implements when the
     result type is REAL.

     @return The result of the operation.
  */
  virtual double real_op()= 0;
  Double_null to_double_null_op()
  {
    // val_real() must be caleed on a separate line. See to_longlong_null()
    double nr= real_op();
    return Double_null(nr, null_value);
  }

  /**
     @brief Performs the operation that this functions implements when the
     result type is DECIMAL.

     @param A pointer where the DECIMAL value will be allocated.
     @return 
       - 0 If the result is NULL
       - The same pointer it was given, with the area initialized to the
         result of the operation.
  */
  virtual my_decimal *decimal_op(my_decimal *)= 0;

  /**
     @brief Performs the operation that this functions implements when the
     result type is a string type.

     @return The result of the operation.
  */
  virtual String *str_op(String *)= 0;

  /**
     @brief Performs the operation that this functions implements when
     field type is DATETIME or DATE.
     @return The result of the operation.
  */
  virtual bool date_op(THD *thd, MYSQL_TIME *res, date_mode_t fuzzydate)= 0;

  /**
     @brief Performs the operation that this functions implements when
     field type is TIME.
     @return The result of the operation.
  */
  virtual bool time_op(THD *thd, MYSQL_TIME *res)= 0;

  virtual bool native_op(THD *thd, Native *native)= 0;
};


/*
  This class resembles SQL standard CASE-alike expressions:
  CASE and its abbreviations COALESCE, NULLIF, IFNULL, IF.

  &lt;case expression&gt; ::=   &lt;case abbreviation&gt;
                        | &lt;case specification&gt;
*/
class Item_func_case_expression: public Item_func_hybrid_field_type
{
public:
  Item_func_case_expression(THD *thd)
   :Item_func_hybrid_field_type(thd)
  { }
  Item_func_case_expression(THD *thd, Item *a)
   :Item_func_hybrid_field_type(thd, a)
  { }
  Item_func_case_expression(THD *thd, Item *a, Item *b)
   :Item_func_hybrid_field_type(thd, a, b)
  { }
  Item_func_case_expression(THD *thd, Item *a, Item *b, Item *c)
   :Item_func_hybrid_field_type(thd, a, b, c)
  { }
  Item_func_case_expression(THD *thd, List&lt;Item&gt; &amp;list):
    Item_func_hybrid_field_type(thd, list)
  { }
  bool find_not_null_fields(table_map allowed) override { return false; }
};


class Item_func_numhybrid: public Item_func_hybrid_field_type
{
protected:

  inline void fix_decimals()
  {
    DBUG_ASSERT(result_type() == DECIMAL_RESULT);
    if (decimals == NOT_FIXED_DEC &amp;&amp; decimals &gt;= max_length)
      decimals= decimal_digits_t(max_length - 1);
  }

public:
  Item_func_numhybrid(THD *thd): Item_func_hybrid_field_type(thd)
  { }
  Item_func_numhybrid(THD *thd, Item *a): Item_func_hybrid_field_type(thd, a)
  { }
  Item_func_numhybrid(THD *thd, Item *a, Item *b):
    Item_func_hybrid_field_type(thd, a, b)
  { }
  Item_func_numhybrid(THD *thd, Item *a, Item *b, Item *c):
    Item_func_hybrid_field_type(thd, a, b, c)
  { }
  Item_func_numhybrid(THD *thd, List&lt;Item&gt; &amp;list):
    Item_func_hybrid_field_type(thd, list)
  { }
  String *str_op(String *str) override { DBUG_ASSERT(0); return 0; }
  bool date_op(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override
  {
    DBUG_ASSERT(0);
    return true;
  }
  bool time_op(THD *thd, MYSQL_TIME *ltime) override
  {
    DBUG_ASSERT(0);
    return true;
  }
  bool native_op(THD *thd, Native *to) override
  {
    DBUG_ASSERT(0);
    return true;
  }
};


/* function where type of result detected by first argument */
class Item_func_num1: public Item_func_numhybrid
{
public:
  Item_func_num1(THD *thd, Item *a): Item_func_numhybrid(thd, a) {}
  Item_func_num1(THD *thd, Item *a, Item *b): Item_func_numhybrid(thd, a, b) {}
  bool check_partition_func_processor(void *int_arg) override { return FALSE; }
  bool check_vcol_func_processor(void *arg) override { return FALSE; }
};


/* Base class for operations like &#039;+&#039;, &#039;-&#039;, &#039;*&#039; */
class Item_num_op :public Item_func_numhybrid
{
protected:
  bool check_arguments() const override
  {
    return false; // Checked by aggregate_for_num_op()
  }
public:
  Item_num_op(THD *thd, Item *a, Item *b): Item_func_numhybrid(thd, a, b) {}
  virtual void result_precision()= 0;

  void print(String *str, enum_query_type query_type) override
  {
    print_op(str, query_type);
  }
  bool fix_type_handler(const Type_aggregator *aggregator);
  void fix_length_and_dec_double()
  {
    aggregate_numeric_attributes_real(args, arg_count);
    max_length= float_length(decimals);
  }
  void fix_length_and_dec_decimal()
  {
    unsigned_flag= args[0]-&gt;unsigned_flag &amp; args[1]-&gt;unsigned_flag;
    result_precision();
    fix_decimals();
  }
  void fix_length_and_dec_int()
  {
    unsigned_flag= args[0]-&gt;unsigned_flag | args[1]-&gt;unsigned_flag;
    result_precision();
    decimals= 0;
    set_handler(type_handler_long_or_longlong());
  }
  void fix_length_and_dec_temporal(bool downcast_decimal_to_int)
  {
    set_handler(&amp;type_handler_newdecimal);
    fix_length_and_dec_decimal();
    if (decimals == 0 &amp;&amp; downcast_decimal_to_int)
      set_handler(type_handler_long_or_longlong());
  }
  bool need_parentheses_in_default() override { return true; }
};


class Item_int_func :public Item_func
{
public:
  /*
    QQ: shouldn&#039;t 20 characters be enough:
    Max unsigned =  18,446,744,073,709,551,615 = 20 digits, 20 characters
    Max signed   =   9,223,372,036,854,775,807 = 19 digits, 19 characters
    Min signed   =  -9,223,372,036,854,775,808 = 19 digits, 20 characters
  */
  Item_int_func(THD *thd): Item_func(thd)
  { collation= DTCollation_numeric(); fix_char_length(21); }
  Item_int_func(THD *thd, Item *a): Item_func(thd, a)
  { collation= DTCollation_numeric(); fix_char_length(21); }
  Item_int_func(THD *thd, Item *a, Item *b): Item_func(thd, a, b)
  { collation= DTCollation_numeric(); fix_char_length(21); }
  Item_int_func(THD *thd, Item *a, Item *b, Item *c): Item_func(thd, a, b, c)
  { collation= DTCollation_numeric(); fix_char_length(21); }
  Item_int_func(THD *thd, Item *a, Item *b, Item *c, Item *d):
    Item_func(thd, a, b, c, d)
  { collation= DTCollation_numeric(); fix_char_length(21); }
  Item_int_func(THD *thd, List&lt;Item&gt; &amp;list): Item_func(thd, list)
  { collation= DTCollation_numeric(); fix_char_length(21); }
  Item_int_func(THD *thd, Item_int_func *item) :Item_func(thd, item)
  { collation= DTCollation_numeric(); }
  double val_real() override;
  String *val_str(String*str) override;
  my_decimal *val_decimal(my_decimal *decimal_value) override
  {
    return val_decimal_from_int(decimal_value);
  }
  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override
  { return get_date_from_int(thd, ltime, fuzzydate); }
  const Type_handler *type_handler() const override= 0;
  bool fix_length_and_dec(THD *thd) override { return FALSE; }
};


class Item_long_func: public Item_int_func
{
public:
  Item_long_func(THD *thd): Item_int_func(thd) { }
  Item_long_func(THD *thd, Item *a): Item_int_func(thd, a) {}
  Item_long_func(THD *thd, Item *a, Item *b): Item_int_func(thd, a, b) {}
  Item_long_func(THD *thd, Item *a, Item *b, Item *c): Item_int_func(thd, a, b, c) {}
  Item_long_func(THD *thd, List&lt;Item&gt; &amp;list): Item_int_func(thd, list) { }
  Item_long_func(THD *thd, Item_long_func *item) :Item_int_func(thd, item) {}
  const Type_handler *type_handler() const override
  {
    if (unsigned_flag)
      return &amp;type_handler_ulong;
    return &amp;type_handler_slong;
  }
  bool fix_length_and_dec(THD *thd) override { max_length= 11; return FALSE; }
};


class Item_long_ge0_func: public Item_int_func
{
public:
  Item_long_ge0_func(THD *thd): Item_int_func(thd) { }
  Item_long_ge0_func(THD *thd, Item *a): Item_int_func(thd, a) {}
  Item_long_ge0_func(THD *thd, Item *a, Item *b): Item_int_func(thd, a, b) {}
  Item_long_ge0_func(THD *thd, Item *a, Item *b, Item *c): Item_int_func(thd, a, b, c) {}
  Item_long_ge0_func(THD *thd, List&lt;Item&gt; &amp;list): Item_int_func(thd, list) { }
  Item_long_ge0_func(THD *thd, Item_long_ge0_func *item) :Item_int_func(thd, item) {}
  const Type_handler *type_handler() const override
  {
    DBUG_ASSERT(!unsigned_flag);
    return &amp;type_handler_slong_ge0;
  }
  bool fix_length_and_dec(THD *) override { max_length= 10; return FALSE; }
};


class Item_func_hash: public Item_int_func
{
public:
  Item_func_hash(THD *thd, List&lt;Item&gt; &amp;item): Item_int_func(thd, item)
  {}
  longlong val_int() override;
  bool fix_length_and_dec(THD *thd) override;
  const Type_handler *type_handler() const override
  { return &amp;type_handler_slong; }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;&lt;hash&gt;&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_hash&gt;(thd, this); }
};

class Item_func_hash_mariadb_100403: public Item_func_hash
{
public:
  Item_func_hash_mariadb_100403(THD *thd, List&lt;Item&gt; &amp;item)
   :Item_func_hash(thd, item)
  {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;&lt;hash_mariadb_100403&gt;&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_hash_mariadb_100403&gt;(thd, this); }
};

class Item_longlong_func: public Item_int_func
{
public:
  Item_longlong_func(THD *thd): Item_int_func(thd) { }
  Item_longlong_func(THD *thd, Item *a): Item_int_func(thd, a) {}
  Item_longlong_func(THD *thd, Item *a, Item *b): Item_int_func(thd, a, b) {}
  Item_longlong_func(THD *thd, Item *a, Item *b, Item *c): Item_int_func(thd, a, b, c) {}
  Item_longlong_func(THD *thd, Item *a, Item *b, Item *c, Item *d):
    Item_int_func(thd, a, b, c, d) {}
  Item_longlong_func(THD *thd, List&lt;Item&gt; &amp;list): Item_int_func(thd, list) { }
  Item_longlong_func(THD *thd, Item_longlong_func *item) :Item_int_func(thd, item) {}
  const Type_handler *type_handler() const override
  {
    if (unsigned_flag)
      return &amp;type_handler_ulonglong;
    return &amp;type_handler_slonglong;
  }
};


class Cursor_ref
{
protected:
  LEX_CSTRING m_cursor_name;
  uint m_cursor_offset;
  class sp_cursor *get_open_cursor_or_error();
  Cursor_ref(const LEX_CSTRING *name, uint offset)
   :m_cursor_name(*name), m_cursor_offset(offset)
  { }
  void print_func(String *str, const LEX_CSTRING &amp;func_name);
};


class Item_func_cursor_rowcount: public Item_longlong_func,
                                 public Cursor_ref
{
public:
  Item_func_cursor_rowcount(THD *thd, const LEX_CSTRING *name, uint offset)
   :Item_longlong_func(thd), Cursor_ref(name, offset)
  {
    set_maybe_null();
  }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;%ROWCOUNT&quot;) };
    return name;
  }
  longlong val_int() override;
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), arg, VCOL_SESSION_FUNC);
  }
  void print(String *str, enum_query_type query_type) override
  {
    return Cursor_ref::print_func(str, func_name_cstring());
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_cursor_rowcount&gt;(thd, this); }
};


class Item_func_connection_id :public Item_long_func
{
  longlong value;

public:
  Item_func_connection_id(THD *thd): Item_long_func(thd) { unsigned_flag=1; }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;connection_id&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override;
  bool fix_fields(THD *thd, Item **ref) override;
  longlong val_int() override { DBUG_ASSERT(fixed()); return value; }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg,
                                     VCOL_SESSION_FUNC);
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_connection_id&gt;(thd, this); }
};


class Item_func_signed :public Item_int_func
{
public:
  Item_func_signed(THD *thd, Item *a): Item_int_func(thd, a)
  {
    unsigned_flag= 0;
  }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;cast_as_signed&quot;) };
    return name;
  }
  const Type_handler *type_handler() const override
  {
    return Type_handler::type_handler_long_or_longlong(max_char_length(),
                                                       false);
  }
  longlong val_int() override
  {
    longlong value= args[0]-&gt;val_int_signed_typecast();
    null_value= args[0]-&gt;null_value;
    return value;
  }
  void fix_length_and_dec_double()
  {
    fix_char_length(MAX_BIGINT_WIDTH);
  }
  void fix_length_and_dec_sint_ge0()
  {
    uint32 digits= args[0]-&gt;decimal_precision();
    DBUG_ASSERT(digits &gt; 0);
    DBUG_ASSERT(digits &lt;= MY_INT64_NUM_DECIMAL_DIGITS);
    fix_char_length(digits + (unsigned_flag ? 0 : 1/*sign*/));
  }
  void fix_length_and_dec_generic()
  {
    uint32 char_length= MY_MIN(args[0]-&gt;max_char_length(),
                               MY_INT64_NUM_DECIMAL_DIGITS);
    /*
      args[0]-&gt;max_char_length() can return 0.
      Reserve max_length to fit at least one character for one digit,
      plus one character for the sign (if signed).
    */
    set_if_bigger(char_length, 1U + (unsigned_flag ? 0 : 1));
    fix_char_length(char_length);
  }
  void fix_length_and_dec_string()
  {
    /*
      For strings, use decimal_int_part() instead of max_char_length().
      This is important for Item_hex_hybrid:
        SELECT CAST(0x1FFFFFFFF AS SIGNED);
      Length is 5, decimal_int_part() is 13.
    */
    uint32 char_length= MY_MIN(args[0]-&gt;decimal_int_part(),
                               MY_INT64_NUM_DECIMAL_DIGITS);
    set_if_bigger(char_length, 1U + (unsigned_flag ? 0 : 1));
    fix_char_length(char_length);
  }
  bool fix_length_and_dec(THD *thd) override
  {
    return args[0]-&gt;type_handler()-&gt;Item_func_signed_fix_length_and_dec(this);
  }
  void print(String *str, enum_query_type query_type) override;
  decimal_digits_t decimal_precision() const override
  { return args[0]-&gt;decimal_precision(); }
  bool need_parentheses_in_default() override { return true; }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_signed&gt;(thd, this); }
};


class Item_func_unsigned :public Item_func_signed
{
public:
  Item_func_unsigned(THD *thd, Item *a): Item_func_signed(thd, a)
  {
    unsigned_flag= 1;
  }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;cast_as_unsigned&quot;) };
    return name;
  }
  const Type_handler *type_handler() const override
  {
    if (max_char_length() &lt;= MY_INT32_NUM_DECIMAL_DIGITS - 1)
      return &amp;type_handler_ulong;
    return &amp;type_handler_ulonglong;
  }
  longlong val_int() override
  {
    longlong value= args[0]-&gt;val_int_unsigned_typecast();
    null_value= args[0]-&gt;null_value;
    return value;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    return args[0]-&gt;type_handler()-&gt;Item_func_unsigned_fix_length_and_dec(this);
  }
  decimal_digits_t decimal_precision() const override
  { return decimal_digits_t(max_length); }
  void print(String *str, enum_query_type query_type) override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_unsigned&gt;(thd, this); }
};


class Item_decimal_typecast :public Item_func
{
  my_decimal decimal_value;
public:
  Item_decimal_typecast(THD *thd, Item *a,
                        decimal_digits_t len, decimal_digits_t dec)
   :Item_func(thd, a)
  {
    decimals= dec;
    collation= DTCollation_numeric();
    fix_char_length(my_decimal_precision_to_length_no_truncation(len, dec,
                                                                 unsigned_flag));
  }
  String *val_str(String *str) override { return VDec(this).to_string(str); }
  double val_real() override { return VDec(this).to_double(); }
  longlong val_int() override { return VDec(this).to_longlong(unsigned_flag); }
  my_decimal *val_decimal(my_decimal*) override;
  bool get_date(THD *thd, MYSQL_TIME *to, date_mode_t mode) override
  {
    return decimal_to_datetime_with_warn(thd, VDec(this).ptr(), to, mode,
                                         NULL, NULL);
  }
  const Type_handler *type_handler() const override
  { return &amp;type_handler_newdecimal; }
  void fix_length_and_dec_generic() {}
  bool fix_length_and_dec(THD *thd) override
  {
    return
      args[0]-&gt;type_handler()-&gt;Item_decimal_typecast_fix_length_and_dec(this);
  }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;decimal_typecast&quot;) };
    return name;
  }
  void print(String *str, enum_query_type query_type) override;
  bool need_parentheses_in_default() override { return true; }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_decimal_typecast&gt;(thd, this); }
};


class Item_real_typecast: public Item_real_func
{
protected:
  double val_real_with_truncate(double max_value);
public:
  Item_real_typecast(THD *thd, Item *a, uint len, uint dec)
   :Item_real_func(thd, a)
  {
    decimals=   (uint8)  dec;
    max_length= (uint32) len;
  }
  bool need_parentheses_in_default() override { return true; }
  void print(String *str, enum_query_type query_type) override;
  void fix_length_and_dec_generic()
  {
    set_maybe_null();
  }
};


class Item_float_typecast :public Item_real_typecast
{
public:
  Item_float_typecast(THD *thd, Item *a)
   :Item_real_typecast(thd, a, MAX_FLOAT_STR_LENGTH, NOT_FIXED_DEC)
  { }
  const Type_handler *type_handler() const override
  { return &amp;type_handler_float; }
  bool fix_length_and_dec(THD *thd) override
  {
    return
      args[0]-&gt;type_handler()-&gt;Item_float_typecast_fix_length_and_dec(this);
  }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;float_typecast&quot;) };
    return name;
  }
  double val_real() override
  {
    return (double) (float) val_real_with_truncate(FLT_MAX);
  }
  String *val_str(String*str) override
  {
    Float nr(Item_float_typecast::val_real());
    if (null_value)
      return 0;
    nr.to_string(str, decimals);
    return str;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_float_typecast&gt;(thd, this); }
};


class Item_double_typecast :public Item_real_typecast
{
public:
  Item_double_typecast(THD *thd, Item *a, uint len, uint dec):
    Item_real_typecast(thd, a, len, dec)
  { }
  bool fix_length_and_dec(THD *thd) override
  {
    return
      args[0]-&gt;type_handler()-&gt;Item_double_typecast_fix_length_and_dec(this);
  }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;double_typecast&quot;) };
    return name;
  }
  double val_real() override { return val_real_with_truncate(DBL_MAX); }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_double_typecast&gt;(thd, this); }
};


class Item_func_additive_op :public Item_num_op
{
public:
  Item_func_additive_op(THD *thd, Item *a, Item *b): Item_num_op(thd, a, b) {}
  void result_precision() override;
  bool check_partition_func_processor(void *int_arg) override {return FALSE;}
  bool check_vcol_func_processor(void *arg) override { return FALSE;}
};


class Item_func_plus :public Item_func_additive_op
{
public:
  Item_func_plus(THD *thd, Item *a, Item *b):
    Item_func_additive_op(thd, a, b) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;+&quot;) };
    return name;
  }
  enum precedence precedence() const override { return ADD_PRECEDENCE; }
  bool fix_length_and_dec(THD *thd) override;
  longlong int_op() override;
  double real_op() override;
  my_decimal *decimal_op(my_decimal *) override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_plus&gt;(thd, this); }
};

class Item_func_minus :public Item_func_additive_op
{
  bool m_depends_on_sql_mode_no_unsigned_subtraction;
public:
  Item_func_minus(THD *thd, Item *a, Item *b):
    Item_func_additive_op(thd, a, b),
    m_depends_on_sql_mode_no_unsigned_subtraction(false)
  { }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;-&quot;) };
    return name;
  }
  enum precedence precedence() const override { return ADD_PRECEDENCE; }
  Sql_mode_dependency value_depends_on_sql_mode() const override;
  longlong int_op() override;
  double real_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  bool fix_length_and_dec(THD *thd) override;
  void fix_unsigned_flag();
  void fix_length_and_dec_double()
  {
    Item_func_additive_op::fix_length_and_dec_double();
    fix_unsigned_flag();
  }
  void fix_length_and_dec_decimal()
  {
    Item_func_additive_op::fix_length_and_dec_decimal();
    fix_unsigned_flag();
  }
  void fix_length_and_dec_int()
  {
    Item_func_additive_op::fix_length_and_dec_int();
    fix_unsigned_flag();
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_minus&gt;(thd, this); }
};


class Item_func_mul :public Item_num_op
{
public:
  Item_func_mul(THD *thd, Item *a, Item *b):
    Item_num_op(thd, a, b) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;*&quot;) };
    return name;
  }
  enum precedence precedence() const override { return MUL_PRECEDENCE; }
  longlong int_op() override;
  double real_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  void result_precision() override;
  bool fix_length_and_dec(THD *thd) override;
  bool check_partition_func_processor(void *int_arg) override {return FALSE;}
  bool check_vcol_func_processor(void *arg) override { return FALSE;}

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_mul&gt;(thd, this); }
};


class Item_func_div :public Item_num_op
{
public:
  uint prec_increment;
  Item_func_div(THD *thd, Item *a, Item *b): Item_num_op(thd, a, b) {}
  longlong int_op() override { DBUG_ASSERT(0); return 0; }
  double real_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;/&quot;) };
    return name;
  }
  enum precedence precedence() const override { return MUL_PRECEDENCE; }
  bool fix_length_and_dec(THD *thd) override;
  void fix_length_and_dec_double();
  void fix_length_and_dec_int();
  void result_precision() override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_div&gt;(thd, this); }
};


class Item_func_int_div :public Item_int_func
{
public:
  Item_func_int_div(THD *thd, Item *a, Item *b): Item_int_func(thd, a, b)
  {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;DIV&quot;) };
    return name;
  }
  enum precedence precedence() const override { return MUL_PRECEDENCE; }
  const Type_handler *type_handler() const override
  { return type_handler_long_or_longlong(); }
  bool fix_length_and_dec(THD *thd) override;
  void print(String *str, enum_query_type query_type) override
  {
    print_op(str, query_type);
  }

  bool check_partition_func_processor(void *int_arg) override {return FALSE;}
  bool check_vcol_func_processor(void *arg) override { return FALSE;}
  bool need_parentheses_in_default() override { return true; }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_int_div&gt;(thd, this); }
};


class Item_func_mod :public Item_num_op
{
public:
  Item_func_mod(THD *thd, Item *a, Item *b): Item_num_op(thd, a, b) {}
  longlong int_op() override;
  double real_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;MOD&quot;) };
    return name;
  }
  enum precedence precedence() const override { return MUL_PRECEDENCE; }
  void result_precision() override;
  bool fix_length_and_dec(THD *thd) override;
  void fix_length_and_dec_double()
  {
    Item_num_op::fix_length_and_dec_double();
    unsigned_flag= args[0]-&gt;unsigned_flag;
  }
  void fix_length_and_dec_decimal()
  {
    result_precision();
    fix_decimals();
  }
  void fix_length_and_dec_int()
  {
    result_precision();
    DBUG_ASSERT(decimals == 0);
    set_handler(type_handler_long_or_longlong());
  }
  bool check_partition_func_processor(void *int_arg) override {return FALSE;}
  bool check_vcol_func_processor(void *arg) override { return FALSE;}

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_mod&gt;(thd, this); }
};


class Item_func_neg :public Item_func_num1
{
public:
  Item_func_neg(THD *thd, Item *a): Item_func_num1(thd, a) {}
  double real_op() override;
  longlong int_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;-&quot;) };
    return name;
  }
  enum Functype functype() const override { return NEG_FUNC; }
  enum precedence precedence() const override { return NEG_PRECEDENCE; }
  void print(String *str, enum_query_type query_type) override
  {
    str-&gt;append(func_name_cstring());
    args[0]-&gt;print_parenthesised(str, query_type, precedence());
  }
  void fix_length_and_dec_int();
  void fix_length_and_dec_double();
  void fix_length_and_dec_decimal();
  bool fix_length_and_dec(THD *thd) override;
  decimal_digits_t decimal_precision() const  override
  { return args[0]-&gt;decimal_precision(); }
  bool need_parentheses_in_default() override { return true; }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_neg&gt;(thd, this); }
};


class Item_func_abs :public Item_func_num1
{
public:
  Item_func_abs(THD *thd, Item *a): Item_func_num1(thd, a) {}
  double real_op() override;
  longlong int_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;abs&quot;) };
    return name;
  }
  void fix_length_and_dec_int();
  void fix_length_and_dec_sint_ge0();
  void fix_length_and_dec_double();
  void fix_length_and_dec_decimal();
  bool fix_length_and_dec(THD *thd) override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_abs&gt;(thd, this); }
};

// A class to handle logarithmic and trigonometric functions

class Item_dec_func :public Item_real_func
{
  bool check_arguments() const override
  { return check_argument_types_can_return_real(0, arg_count); }
 public:
  Item_dec_func(THD *thd, Item *a): Item_real_func(thd, a) {}
  Item_dec_func(THD *thd, Item *a, Item *b): Item_real_func(thd, a, b) {}
  bool fix_length_and_dec(THD *thd) override
  {
    decimals= NOT_FIXED_DEC;
    max_length= float_length(decimals);
    set_maybe_null();
    return FALSE;
  }
};

class Item_func_exp :public Item_dec_func
{
public:
  Item_func_exp(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;exp&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_exp&gt;(thd, this); }
};


class Item_func_ln :public Item_dec_func
{
public:
  Item_func_ln(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;ln&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_ln&gt;(thd, this); }
};


class Item_func_log :public Item_dec_func
{
public:
  Item_func_log(THD *thd, Item *a): Item_dec_func(thd, a) {}
  Item_func_log(THD *thd, Item *a, Item *b): Item_dec_func(thd, a, b) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;log&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_log&gt;(thd, this); }
};


class Item_func_log2 :public Item_dec_func
{
public:
  Item_func_log2(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;log2&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_log2&gt;(thd, this); }
};


class Item_func_log10 :public Item_dec_func
{
public:
  Item_func_log10(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;log10&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_log10&gt;(thd, this); }
};


class Item_func_sqrt :public Item_dec_func
{
public:
  Item_func_sqrt(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;sqrt&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_sqrt&gt;(thd, this); }
};


class Item_func_pow :public Item_dec_func
{
public:
  Item_func_pow(THD *thd, Item *a, Item *b): Item_dec_func(thd, a, b) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;pow&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_pow&gt;(thd, this); }
};


class Item_func_acos :public Item_dec_func
{
public:
  Item_func_acos(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;acos&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_acos&gt;(thd, this); }
};

class Item_func_asin :public Item_dec_func
{
public:
  Item_func_asin(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;asin&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_asin&gt;(thd, this); }
};

class Item_func_atan :public Item_dec_func
{
public:
  Item_func_atan(THD *thd, Item *a): Item_dec_func(thd, a) {}
  Item_func_atan(THD *thd, Item *a, Item *b): Item_dec_func(thd, a, b) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;atan&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_atan&gt;(thd, this); }
};

class Item_func_cos :public Item_dec_func
{
public:
  Item_func_cos(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;cos&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_cos&gt;(thd, this); }
};

class Item_func_sin :public Item_dec_func
{
public:
  Item_func_sin(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;sin&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_sin&gt;(thd, this); }
};

class Item_func_tan :public Item_dec_func
{
public:
  Item_func_tan(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;tan&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_tan&gt;(thd, this); }
};

class Item_func_cot :public Item_dec_func
{
public:
  Item_func_cot(THD *thd, Item *a): Item_dec_func(thd, a) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;cot&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_cot&gt;(thd, this); }
};


class Item_func_int_val :public Item_func_hybrid_field_type
{
public:
  Item_func_int_val(THD *thd, Item *a): Item_func_hybrid_field_type(thd, a) {}
  bool check_partition_func_processor(void *int_arg) override { return FALSE; }
  bool check_vcol_func_processor(void *arg) override { return FALSE; }
  virtual decimal_round_mode round_mode() const= 0;
  void fix_length_and_dec_double();
  void fix_length_and_dec_int_or_decimal();
  void fix_length_and_dec_time()
  {
    fix_attributes_time(0);
    set_handler(&amp;type_handler_time2);
  }
  void fix_length_and_dec_datetime()
  {
    fix_attributes_datetime(0);
    set_handler(&amp;type_handler_datetime2);
    // Thinks like CEILING(TIMESTAMP&#039;0000-01-01 23:59:59.9&#039;) returns NULL
    set_maybe_null();
  }
  bool fix_length_and_dec(THD *thd) override;
  String *str_op(String *str) override { DBUG_ASSERT(0); return 0; }
  bool native_op(THD *thd, Native *to) override;
};


class Item_func_ceiling :public Item_func_int_val
{
public:
  Item_func_ceiling(THD *thd, Item *a): Item_func_int_val(thd, a) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;ceiling&quot;) };
    return name;
  }
  decimal_round_mode round_mode() const override { return CEILING; }
  longlong int_op() override;
  double real_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  bool date_op(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override;
  bool time_op(THD *thd, MYSQL_TIME *ltime) override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_ceiling&gt;(thd, this); }
};


class Item_func_floor :public Item_func_int_val
{
public:
  Item_func_floor(THD *thd, Item *a): Item_func_int_val(thd, a) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;floor&quot;) };
    return name;
  }
  decimal_round_mode round_mode() const override { return FLOOR; }
  longlong int_op() override;
  double real_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  bool date_op(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override;
  bool time_op(THD *thd, MYSQL_TIME *ltime) override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_floor&gt;(thd, this); }
};

/* This handles round and truncate */

class Item_func_round :public Item_func_hybrid_field_type
{
  bool truncate;
  void fix_length_and_dec_decimal(uint decimals_to_set);
  void fix_length_and_dec_double(uint decimals_to_set);
  bool test_if_length_can_increase();
public:
  Item_func_round(THD *thd, Item *a, Item *b, bool trunc_arg)
    :Item_func_hybrid_field_type(thd, a, b), truncate(trunc_arg) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING truncate_name= {STRING_WITH_LEN(&quot;truncate&quot;) };
    static LEX_CSTRING round_name= {STRING_WITH_LEN(&quot;round&quot;) };
    return truncate ? truncate_name : round_name;
  }
  double real_op() override;
  longlong int_op() override;
  my_decimal *decimal_op(my_decimal *) override;
  bool date_op(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override;
  bool time_op(THD *thd, MYSQL_TIME *ltime) override;
  bool native_op(THD *thd, Native *to) override;
  String *str_op(String *str) override
  {
    DBUG_ASSERT(0);
    return NULL;
  }
  void fix_arg_decimal();
  void fix_arg_int(const Type_handler *preferred,
                   const Type_std_attributes *preferred_attributes,
                   bool use_decimal_on_length_increase);
  void fix_arg_slong_ge0();
  void fix_arg_hex_hybrid();
  void fix_arg_double();
  void fix_arg_time();
  void fix_arg_datetime();
  void fix_arg_temporal(const Type_handler *h, uint int_part_length);
  bool fix_length_and_dec(THD *thd) override
  {
    /*
      We don&#039;t want to translate ENUM/SET to CHAR here.
      So let&#039;s real_type_handler(), not type_handler().
    */
    return args[0]-&gt;real_type_handler()-&gt;Item_func_round_fix_length_and_dec(this);
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_round&gt;(thd, this); }
};


class Item_func_rand :public Item_real_func
{
  struct my_rnd_struct *rand;
  bool first_eval; // TRUE if val_real() is called 1st time
  bool check_arguments() const override
  { return check_argument_types_can_return_int(0, arg_count); }
  void seed_random (Item * val);
public:
  Item_func_rand(THD *thd, Item *a):
    Item_real_func(thd, a), rand(0), first_eval(TRUE) {}
  Item_func_rand(THD *thd): Item_real_func(thd) {}
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;rand&quot;) };
    return name;
  }
  bool const_item() const override { return 0; }
  void update_used_tables() override;
  bool fix_fields(THD *thd, Item **ref) override;
  void cleanup() override { first_eval= TRUE; Item_real_func::cleanup(); }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_SESSION_FUNC);
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_rand&gt;(thd, this); }
};


class Item_func_rownum final :public Item_longlong_func
{
  /*
    This points to a variable that contains the number of rows
    accpted so far in the result set
  */
  ha_rows *accepted_rows;
  SELECT_LEX *select;
public:
  Item_func_rownum(THD *thd);
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;rownum&quot;) };
    return name;
  }
  enum Functype functype() const override { return ROWNUM_FUNC; }
  void update_used_tables() override {}
  bool const_item() const override { return 0; }
  void fix_after_optimize(THD *thd) override;
  bool fix_length_and_dec(THD *thd) override
  {
    unsigned_flag= 1;
    used_tables_cache= RAND_TABLE_BIT;
    const_item_cache=0;
    set_maybe_null();
    return FALSE;
  }
  void cleanup() override
  {
    Item_longlong_func::cleanup();
    /* Ensure we don&#039;t point to freed memory */
    accepted_rows= 0;
  }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg,
                                     VCOL_IMPOSSIBLE);
  }
  bool check_handler_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg,
                                     VCOL_IMPOSSIBLE);
  }
  /* This function is used in insert, update and delete */
  void store_pointer_to_row_counter(ha_rows *row_counter)
  {
    accepted_rows= row_counter;
  }

protected:
  Item *shallow_copy(THD *thd) const override { return 0; }
};

void fix_rownum_pointers(THD *thd, SELECT_LEX *select_lex, ha_rows *ptr);


class Item_func_sign :public Item_long_func
{
  bool check_arguments() const override
  { return args[0]-&gt;check_type_can_return_real(func_name_cstring()); }
public:
  Item_func_sign(THD *thd, Item *a): Item_long_func(thd, a) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;sign&quot;) };
    return name;
  }
  decimal_digits_t decimal_precision() const override { return 1; }
  bool fix_length_and_dec(THD *thd) override { fix_char_length(2); return FALSE; }
  longlong val_int() override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_sign&gt;(thd, this); }
};


class Item_func_units :public Item_real_func
{
  LEX_CSTRING name;
  double mul,add;
  bool check_arguments() const override
  { return check_argument_types_can_return_real(0, arg_count); }
public:
  Item_func_units(THD *thd, char *name_arg, Item *a, double mul_arg,
                  double add_arg):
    Item_real_func(thd, a), mul(mul_arg), add(add_arg)
  {
    name.str= name_arg;
    name.length= strlen(name_arg);
  }
  double val_real() override;
  LEX_CSTRING func_name_cstring() const override { return name; }
  bool fix_length_and_dec(THD *thd) override
  {
    decimals= NOT_FIXED_DEC;
    max_length= float_length(decimals);
    return FALSE;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_units&gt;(thd, this); }
};


/**
  Item_func_min_max does not derive from Item_func_hybrid_field_type
  because the way how its methods val_xxx() and get_date() work depend
  not only by its arguments, but also on the context in which
  LEAST() and GREATEST() appear.
  For example, using Item_func_min_max in a CAST like this:
    CAST(LEAST(&#039;11&#039;,&#039;2&#039;) AS SIGNED)
  forces Item_func_min_max to compare the arguments as numbers rather
  than strings.
  Perhaps this should be changed eventually (see MDEV-5893).
*/
class Item_func_min_max :public Item_hybrid_func
{
  String tmp_value;
  int cmp_sign;
protected:
  bool check_arguments() const override
  {
    return false; // Checked by aggregate_for_min_max()
  }
  bool fix_attributes(Item **item, uint nitems);
public:
  Item_func_min_max(THD *thd, List&lt;Item&gt; &amp;list, int cmp_sign_arg):
    Item_hybrid_func(thd, list), cmp_sign(cmp_sign_arg)
  {}
  String *val_str_native(String *str);
  double val_real_native();
  longlong val_int_native();
  longlong val_uint_native();
  my_decimal *val_decimal_native(my_decimal *);
  bool get_date_native(THD *thd, MYSQL_TIME *res, date_mode_t fuzzydate);
  bool get_time_native(THD *thd, MYSQL_TIME *res);

  double val_real() override
  {
    DBUG_ASSERT(fixed());
    return Item_func_min_max::type_handler()-&gt;
             Item_func_min_max_val_real(this);
  }
  longlong val_int() override
  {
    DBUG_ASSERT(fixed());
    return Item_func_min_max::type_handler()-&gt;
             Item_func_min_max_val_int(this);
  }
  String *val_str(String *str) override
  {
    DBUG_ASSERT(fixed());
    return Item_func_min_max::type_handler()-&gt;
             Item_func_min_max_val_str(this, str);
  }
  my_decimal *val_decimal(my_decimal *dec) override
  {
    DBUG_ASSERT(fixed());
    return Item_func_min_max::type_handler()-&gt;
             Item_func_min_max_val_decimal(this, dec);
  }
  bool get_date(THD *thd, MYSQL_TIME *res, date_mode_t fuzzydate) override
  {
    DBUG_ASSERT(fixed());
    return Item_func_min_max::type_handler()-&gt;
             Item_func_min_max_get_date(thd, this, res, fuzzydate);
  }
  bool val_native(THD *thd, Native *to) override;
  void aggregate_attributes_real(Item **items, uint nitems)
  {
    /*
      Aggregating attributes for the double data type for LEAST/GREATEST
      is almost the same with aggregating for CASE-alike hybrid functions,
      (CASE..THEN, COALESCE, IF, etc).
      There is one notable difference though, when a numeric argument is mixed
      with a string argument:
      - CASE-alike functions return a string data type in such cases
        COALESCE(10,&#039;x&#039;) -&gt; VARCHAR(2) = &#039;10&#039;
      - LEAST/GREATEST returns double:
        GREATEST(10,&#039;10e4&#039;) -&gt; DOUBLE = 100000
      As the string argument can represent a number in the scientific notation,
      like in the example above, max_length of the result can be longer than
      max_length of the arguments. To handle this properly, max_length is
      additionally assigned to the result of float_length(decimals).
    */
    Item_func::aggregate_attributes_real(items, nitems);
    max_length= float_length(decimals);
  }
  bool fix_length_and_dec(THD *thd) override
  {
    if (aggregate_for_min_max(func_name_cstring(), args, arg_count))
      return true;
    fix_attributes(args, arg_count);
    return false;
  }
};

class Item_func_min :public Item_func_min_max
{
public:
  Item_func_min(THD *thd, List&lt;Item&gt; &amp;list): Item_func_min_max(thd, list, 1) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;least&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_min&gt;(thd, this); }
};

class Item_func_max :public Item_func_min_max
{
public:
  Item_func_max(THD *thd, List&lt;Item&gt; &amp;list): Item_func_min_max(thd, list, -1) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;greatest&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_max&gt;(thd, this); }
};


/* 
  Objects of this class are used for ROLLUP queries to wrap up 
  each constant item referred to in GROUP BY list. 
*/

class Item_func_rollup_const :public Item_func
{
public:
  Item_func_rollup_const(THD *thd, Item *a): Item_func(thd, a)
  {
    name= a-&gt;name;
  }
  double val_real() override { return val_real_from_item(args[0]); }
  longlong val_int() override { return val_int_from_item(args[0]); }
  String *val_str(String *str) override
  { return val_str_from_item(args[0], str); }
  bool val_native(THD *thd, Native *to) override
  { return val_native_from_item(thd, args[0], to); }
  my_decimal *val_decimal(my_decimal *dec) override
    { return val_decimal_from_item(args[0], dec); }
  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override
    { return get_date_from_item(thd, args[0], ltime, fuzzydate); }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;rollup_const&quot;) };
    return name;
  }
  bool const_item() const override { return 0; }
  const Type_handler *type_handler() const override
  { return args[0]-&gt;type_handler(); }
  bool fix_length_and_dec(THD *thd) override
  {
    Type_std_attributes::set(*args[0]);
    return FALSE;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_rollup_const&gt;(thd, this); }
};


class Item_long_func_length: public Item_long_func
{
  bool check_arguments() const override
  { return args[0]-&gt;check_type_can_return_str(func_name_cstring()); }
public:
  Item_long_func_length(THD *thd, Item *a): Item_long_func(thd, a) {}
  bool fix_length_and_dec(THD *thd) override { max_length=10; return FALSE; }
};


class Item_func_octet_length :public Item_long_func_length
{
  String value;
public:
  Item_func_octet_length(THD *thd, Item *a): Item_long_func_length(thd, a) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;octet_length&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_octet_length&gt;(thd, this); }
};

class Item_func_bit_length :public Item_longlong_func
{
  String value;
public:
  Item_func_bit_length(THD *thd, Item *a): Item_longlong_func(thd, a) {}
  bool fix_length_and_dec(THD *thd) override
  {
    max_length= 11; // 0x100000000*8 = 34,359,738,368
    return FALSE;
  }
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;bit_length&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_bit_length&gt;(thd, this); }
};

class Item_func_char_length :public Item_long_func_length
{
  String value;
public:
  Item_func_char_length(THD *thd, Item *a): Item_long_func_length(thd, a) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;char_length&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_char_length&gt;(thd, this); }
};

class Item_func_coercibility :public Item_long_func
{
  longlong m_cached_collation_derivation;

  bool check_arguments() const override
  { return args[0]-&gt;check_type_can_return_str(func_name_cstring()); }
public:
  Item_func_coercibility(THD *thd, Item *a): Item_long_func(thd, a) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;coercibility&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override;
  bool eval_not_null_tables(void *) override
  {
    not_null_tables_cache= 0;
    return false;
  }
  bool find_not_null_fields(table_map allowed) override
  {
    return false;
  }
  Item* propagate_equal_fields(THD *thd, const Context &amp;ctx, COND_EQUAL *cond)
    override
  { return this; }
  bool const_item() const override { return true; }
  table_map used_tables() const override { return 0; }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_coercibility&gt;(thd, this); }
};


/*
  In the corner case LOCATE could return (4,294,967,296 + 1),
  which would not fit into Item_long_func range.
  But string lengths are limited with max_allowed_packet,
  which cannot be bigger than 1024*1024*1024.
*/
class Item_func_locate :public Item_long_func
{
  bool check_arguments() const override
  {
    return check_argument_types_can_return_str(0, 2) ||
           (arg_count &gt; 2 &amp;&amp; args[2]-&gt;check_type_can_return_int(func_name_cstring()));
  }
  String value1,value2;
  DTCollation cmp_collation;
public:
  Item_func_locate(THD *thd, Item *a, Item *b)
   :Item_long_func(thd, a, b) {}
  Item_func_locate(THD *thd, Item *a, Item *b, Item *c)
   :Item_long_func(thd, a, b, c) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;locate&quot;) };
    return name;
  }
  longlong val_int() override;
  bool fix_length_and_dec(THD *thd) override
  {
    max_length= MY_INT32_NUM_DECIMAL_DIGITS;
    return agg_arg_charsets_for_comparison(cmp_collation, args, 2);
  }
  void print(String *str, enum_query_type query_type) override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_locate&gt;(thd, this); }
};


class Item_func_field :public Item_long_func
{
  String value,tmp;
  Item_result cmp_type;
  DTCollation cmp_collation;
public:
  Item_func_field(THD *thd, List&lt;Item&gt; &amp;list): Item_long_func(thd, list) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;field&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_field&gt;(thd, this); }
};


class Item_func_ascii :public Item_long_func
{
  bool check_arguments() const override
  { return check_argument_types_can_return_str(0, arg_count); }
  String value;
public:
  Item_func_ascii(THD *thd, Item *a): Item_long_func(thd, a) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;ascii&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override { max_length=3; return FALSE; }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_ascii&gt;(thd, this); }
};

class Item_func_ord :public Item_long_func
{
  bool check_arguments() const override
  { return args[0]-&gt;check_type_can_return_str(func_name_cstring()); }
  String value;
public:
  Item_func_ord(THD *thd, Item *a): Item_long_func(thd, a) {}
  bool fix_length_and_dec(THD *thd) override { fix_char_length(7); return FALSE; }
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;ord&quot;) };
    return name;
  }

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_ord&gt;(thd, this); }
};

class Item_func_find_in_set :public Item_long_func
{
  bool check_arguments() const override
  { return check_argument_types_can_return_str(0, 2); }
  String value,value2;
  uint enum_value;
  ulonglong enum_bit;
  DTCollation cmp_collation;
public:
  Item_func_find_in_set(THD *thd, Item *a, Item *b):
    Item_long_func(thd, a, b), enum_value(0) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;find_in_set&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override;

protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_find_in_set&gt;(thd, this); }
};

/* Base class for all bit functions: &#039;~&#039;, &#039;|&#039;, &#039;^&#039;, &#039;&amp;&#039;, &#039;&gt;&gt;&#039;, &#039;&lt;&lt;&#039; */

class Item_func_bit_operator: public Item_handled_func
{
  bool check_arguments() const override
  { return check_argument_types_can_return_int(0, arg_count); }
protected:
  bool fix_length_and_dec_op1_std(const Handler *ha_int, const Handler *ha_dec)
  {
    set_func_handler(args[0]-&gt;cmp_type() == INT_RESULT ? ha_int : ha_dec);
    return m_func_handler-&gt;fix_length_and_dec(this);
  }
  bool fix_length_and_dec_op2_std(const Handler *ha_int, const Handler *ha_dec)
  {
    set_func_handler(args[0]-&gt;cmp_type() == INT_RESULT &amp;&amp;
                     args[1]-&gt;cmp_type() == INT_RESULT ? ha_int : ha_dec);
    return m_func_handler-&gt;fix_length_and_dec(this);
  }
public:
  Item_func_bit_operator(THD *thd, Item *a)
   :Item_handled_func(thd, a) {}
  Item_func_bit_operator(THD *thd, Item *a, Item *b)
   :Item_handled_func(thd, a, b) {}
  void print(String *str, enum_query_type query_type) override
  {
    print_op(str, query_type);
  }
  bool need_parentheses_in_default() override { return true; }
};

class Item_func_bit_or :public Item_func_bit_operator
{
public:
  Item_func_bit_or(THD *thd, Item *a, Item *b)
   :Item_func_bit_operator(thd, a, b) {}
  bool fix_length_and_dec(THD *thd) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;|&quot;) };
    return name;
  }
  enum precedence precedence() const override { return BITOR_PRECEDENCE; }
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_bit_or&gt;(thd, this); }
};

class Item_func_bit_and :public Item_func_bit_operator
{
public:
  Item_func_bit_and(THD *thd, Item *a, Item *b)
   :Item_func_bit_operator(thd, a, b) {}
  bool fix_length_and_dec(THD *thd) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;&amp;&quot;) };
    return name;
  }
  enum precedence precedence() const override { return BITAND_PRECEDENCE; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_bit_and&gt;(thd, this); }
};

class Item_func_bit_count :public Item_handled_func
{
  bool check_arguments() const override
  { return args[0]-&gt;check_type_can_return_int(func_name_cstring()); }
public:
  Item_func_bit_count(THD *thd, Item *a): Item_handled_func(thd, a) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;bit_count&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override;
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_bit_count&gt;(thd, this); }
};

class Item_func_shift_left :public Item_func_bit_operator
{
public:
  Item_func_shift_left(THD *thd, Item *a, Item *b)
   :Item_func_bit_operator(thd, a, b) {}
  bool fix_length_and_dec(THD *thd) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;&lt;&lt;&quot;) };
    return name;
  }
  enum precedence precedence() const override { return SHIFT_PRECEDENCE; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_shift_left&gt;(thd, this); }
};

class Item_func_shift_right :public Item_func_bit_operator
{
public:
  Item_func_shift_right(THD *thd, Item *a, Item *b)
   :Item_func_bit_operator(thd, a, b) {}
  bool fix_length_and_dec(THD *thd) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;&gt;&gt;&quot;) };
    return name;
  }
  enum precedence precedence() const override { return SHIFT_PRECEDENCE; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_shift_right&gt;(thd, this); }
};

class Item_func_bit_neg :public Item_func_bit_operator
{
public:
  Item_func_bit_neg(THD *thd, Item *a): Item_func_bit_operator(thd, a) {}
  bool fix_length_and_dec(THD *thd) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;~&quot;) };
    return name;
  }
  enum precedence precedence() const override { return NEG_PRECEDENCE; }
  void print(String *str, enum_query_type query_type) override
  {
    str-&gt;append(func_name_cstring());
    args[0]-&gt;print_parenthesised(str, query_type, precedence());
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_bit_neg&gt;(thd, this); }
};


class Item_func_last_insert_id :public Item_longlong_func
{
  bool check_arguments() const override
  { return check_argument_types_can_return_int(0, arg_count); }
public:
  Item_func_last_insert_id(THD *thd): Item_longlong_func(thd) {}
  Item_func_last_insert_id(THD *thd, Item *a): Item_longlong_func(thd, a) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;last_insert_id&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    unsigned_flag= true;
    if (arg_count)
      max_length= args[0]-&gt;max_length;
    return FALSE;
  }
  bool fix_fields(THD *thd, Item **ref) override;
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_last_insert_id&gt;(thd, this); }
};


class Item_func_benchmark :public Item_long_func
{
  bool check_arguments() const override
  {
    return args[0]-&gt;check_type_can_return_int(func_name_cstring()) ||
           args[1]-&gt;check_type_scalar(func_name_cstring());
  }
public:
  Item_func_benchmark(THD *thd, Item *count_expr, Item *expr):
    Item_long_func(thd, count_expr, expr)
  {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;benchmark&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    max_length=1;
    base_flags&amp;= ~item_base_t::MAYBE_NULL;
    return FALSE;
  }
  void print(String *str, enum_query_type query_type) override;
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_benchmark&gt;(thd, this); }
};


void item_func_sleep_init(void);
void item_func_sleep_free(void);

class Item_func_sleep :public Item_long_func
{
  bool check_arguments() const override
  { return args[0]-&gt;check_type_can_return_real(func_name_cstring()); }
public:
  Item_func_sleep(THD *thd, Item *a): Item_long_func(thd, a) {}
  bool fix_length_and_dec(THD *thd) override { fix_char_length(1); return FALSE; }
  bool const_item() const override { return 0; }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;sleep&quot;) };
    return name;
  }
  table_map used_tables() const override
  {
    return used_tables_cache | RAND_TABLE_BIT;
  }
  bool is_expensive() override { return 1; }
  longlong val_int() override;
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_sleep&gt;(thd, this); }
};


#ifdef HAVE_DLOPEN

class Item_udf_func :public Item_func
{
  /**
    Mark &quot;this&quot; as non-deterministic if it uses no tables
    and is not a constant at the same time.
  */
  void set_non_deterministic_if_needed()
  {
    if (!const_item_cache &amp;&amp; !used_tables_cache)
      used_tables_cache= RAND_TABLE_BIT;
  }
protected:
  udf_handler udf;
  bool is_expensive_processor(void *arg) override { return TRUE; }

  class VDec_udf: public Dec_ptr_and_buffer
  {
  public:
    VDec_udf(Item_udf_func *func, udf_handler *udf)
    {
      my_bool tmp_null_value;
      m_ptr= udf-&gt;val_decimal(&amp;tmp_null_value, &amp;m_buffer);
      DBUG_ASSERT(is_null() == (tmp_null_value != 0));
      func-&gt;null_value= is_null();
    }
  };

public:
  Item_udf_func(THD *thd, udf_func *udf_arg):
    Item_func(thd), udf(udf_arg) {}
  Item_udf_func(THD *thd, udf_func *udf_arg, List&lt;Item&gt; &amp;list):
    Item_func(thd, list), udf(udf_arg) {}
  LEX_CSTRING func_name_cstring() const override
  {
    const char *tmp= udf.name();
    return { tmp, strlen(tmp) };
  }
  enum Functype functype() const override { return UDF_FUNC; }
  bool fix_fields(THD *thd, Item **ref) override
  {
    DBUG_ASSERT(fixed() == 0);
    bool res= udf.fix_fields(thd, this, arg_count, args);
    set_non_deterministic_if_needed();
    base_flags|= item_base_t::FIXED;
    return res;
  }
  void fix_num_length_and_dec();
  void update_used_tables() override
  {
    /*
      TODO: Make a member in UDF_INIT and return if a UDF is deterministic or
      not.
      Currently UDF_INIT has a member (const_item) that is an in/out 
      parameter to the init() call.
      The code in udf_handler::fix_fields also duplicates the arguments 
      handling code in Item_func::fix_fields().
      
      The lack of information if a UDF is deterministic makes writing
      a correct update_used_tables() for UDFs impossible.
      One solution to this would be :
       - Add a is_deterministic member of UDF_INIT
       - (optionally) deprecate the const_item member of UDF_INIT
       - Take away the duplicate code from udf_handler::fix_fields() and
         make Item_udf_func call Item_func::fix_fields() to process its 
         arguments as for any other function.
       - Store the deterministic flag returned by &lt;udf&gt;_init into the 
       udf_handler. 
       - Don&#039;t implement Item_udf_func::fix_fields, implement
       Item_udf_func::fix_length_and_dec() instead (similar to non-UDF
       functions).
       - Override Item_func::update_used_tables to call 
       Item_func::update_used_tables() and add a RAND_TABLE_BIT to the 
       result of Item_func::update_used_tables() if the UDF is 
       non-deterministic.
       - (optionally) rename RAND_TABLE_BIT to NONDETERMINISTIC_BIT to
       better describe its usage.
       
      The above would require a change of the UDF API.
      Until that change is done here&#039;s how the current code works:
      We call Item_func::update_used_tables() only when we know that
      the function depends on real non-const tables and is deterministic.
      This can be done only because we know that the optimizer will
      call update_used_tables() only when there&#039;s possibly a new const
      table. So update_used_tables() can only make a Item_func more
      constant than it is currently.
      That&#039;s why we don&#039;t need to do anything if a function is guaranteed
      to return non-constant (it&#039;s non-deterministic) or is already a
      const.
    */  
    if ((used_tables_cache &amp; ~PSEUDO_TABLE_BITS) &amp;&amp; 
        !(used_tables_cache &amp; RAND_TABLE_BIT))
    {
      Item_func::update_used_tables();
      set_non_deterministic_if_needed();
    }
  }
  void cleanup() override;
  bool eval_not_null_tables(void *opt_arg) override
  {
    not_null_tables_cache= 0;
    return 0;
  }
  bool find_not_null_fields(table_map allowed) override
  {
    return false;
  }
  bool is_expensive() override { return 1; }
  void print(String *str, enum_query_type query_type) override;
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg,
                                     VCOL_NON_DETERMINISTIC);
  }
  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override
  {
    return type_handler()-&gt;Item_get_date_with_warn(thd, this, ltime, fuzzydate);
  }
  bool excl_dep_on_grouping_fields(st_select_lex *sel) override
  { return false; }
};


class Item_func_udf_float :public Item_udf_func
{
 public:
  Item_func_udf_float(THD *thd, udf_func *udf_arg):
    Item_udf_func(thd, udf_arg) {}
  Item_func_udf_float(THD *thd, udf_func *udf_arg,
                      List&lt;Item&gt; &amp;list):
    Item_udf_func(thd, udf_arg, list) {}
  longlong val_int() override
  {
    DBUG_ASSERT(fixed());
    return Converter_double_to_longlong(Item_func_udf_float::val_real(),
                                        unsigned_flag).result();
  }
  my_decimal *val_decimal(my_decimal *dec_buf) override
  {
    double res=val_real();
    if (null_value)
      return NULL;
    double2my_decimal(E_DEC_FATAL_ERROR, res, dec_buf);
    return dec_buf;
  }
  double val_real() override;
  String *val_str(String *str) override;
  const Type_handler *type_handler() const override
  { return &amp;type_handler_double; }
  bool fix_length_and_dec(THD *thd) override { fix_num_length_and_dec(); return FALSE; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_udf_float&gt;(thd, this); }
};


class Item_func_udf_int :public Item_udf_func
{
public:
  Item_func_udf_int(THD *thd, udf_func *udf_arg):
    Item_udf_func(thd, udf_arg) {}
  Item_func_udf_int(THD *thd, udf_func *udf_arg,
                    List&lt;Item&gt; &amp;list):
    Item_udf_func(thd, udf_arg, list) {}
  longlong val_int() override;
  double val_real() override { return (double) Item_func_udf_int::val_int(); }
  my_decimal *val_decimal(my_decimal *decimal_value) override
  {
    return val_decimal_from_int(decimal_value);
  }
  String *val_str(String *str) override;
  const Type_handler *type_handler() const override
  {
    if (unsigned_flag)
      return &amp;type_handler_ulonglong;
    return &amp;type_handler_slonglong;
  }
  bool fix_length_and_dec(THD *thd) override { decimals= 0; max_length= 21; return FALSE; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_udf_int&gt;(thd, this); }
};


class Item_func_udf_decimal :public Item_udf_func
{
public:
  Item_func_udf_decimal(THD *thd, udf_func *udf_arg):
    Item_udf_func(thd, udf_arg) {}
  Item_func_udf_decimal(THD *thd, udf_func *udf_arg, List&lt;Item&gt; &amp;list):
    Item_udf_func(thd, udf_arg, list) {}
  longlong val_int() override
  {
    return VDec_udf(this, &amp;udf).to_longlong(unsigned_flag);
  }
  double val_real() override
  {
    return VDec_udf(this, &amp;udf).to_double();
  }
  my_decimal *val_decimal(my_decimal *) override;
  String *val_str(String *str) override
  {
    return VDec_udf(this, &amp;udf).to_string_round(str, decimals);
  }
  const Type_handler *type_handler() const override
  { return &amp;type_handler_newdecimal; }
  bool fix_length_and_dec(THD *thd) override { fix_num_length_and_dec(); return FALSE; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_udf_decimal&gt;(thd, this); }
};


class Item_func_udf_str :public Item_udf_func
{
public:
  Item_func_udf_str(THD *thd, udf_func *udf_arg):
    Item_udf_func(thd, udf_arg) {}
  Item_func_udf_str(THD *thd, udf_func *udf_arg, List&lt;Item&gt; &amp;list):
    Item_udf_func(thd, udf_arg, list) {}
  String *val_str(String *) override;
  double val_real() override
  {
    int err_not_used;
    char *end_not_used;
    String *res;
    res= val_str(&amp;str_value);
    return res ? res-&gt;charset()-&gt;strntod((char*) res-&gt;ptr(), res-&gt;length(),
                                         &amp;end_not_used, &amp;err_not_used) : 0.0;
  }
  longlong val_int() override
  {
    int err_not_used;
    String *res;  res=val_str(&amp;str_value);
    return res ? res-&gt;charset()-&gt;strntoll(res-&gt;ptr(),res-&gt;length(),10,
                                          (char**) 0, &amp;err_not_used) : (longlong) 0;
  }
  my_decimal *val_decimal(my_decimal *dec_buf) override
  {
    String *res=val_str(&amp;str_value);
    if (!res)
      return NULL;
    string2my_decimal(E_DEC_FATAL_ERROR, res, dec_buf);
    return dec_buf;
  }
  const Type_handler *type_handler() const override
  { return string_type_handler(); }
  bool fix_length_and_dec(THD *thd) override;
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_udf_str&gt;(thd, this); }
};

#else /* Dummy functions to get yy_*.cc files compiled */

class Item_func_udf_float :public Item_real_func
{
 public:
  Item_func_udf_float(THD *thd, udf_func *udf_arg):
    Item_real_func(thd) {}
  Item_func_udf_float(THD *thd, udf_func *udf_arg, List&lt;Item&gt; &amp;list):
    Item_real_func(thd, list) {}
  double val_real() { DBUG_ASSERT(fixed()); return 0.0; }
};


class Item_func_udf_int :public Item_int_func
{
public:
  Item_func_udf_int(THD *thd, udf_func *udf_arg):
    Item_int_func(thd) {}
  Item_func_udf_int(THD *thd, udf_func *udf_arg, List&lt;Item&gt; &amp;list):
    Item_int_func(thd, list) {}
  const Type_handler *type_handler() const override
  { return &amp;type_handler_slonglong; }
  longlong val_int() { DBUG_ASSERT(fixed()); return 0; }
};


class Item_func_udf_decimal :public Item_int_func
{
public:
  Item_func_udf_decimal(THD *thd, udf_func *udf_arg):
    Item_int_func(thd) {}
  Item_func_udf_decimal(THD *thd, udf_func *udf_arg, List&lt;Item&gt; &amp;list):
    Item_int_func(thd, list) {}
  const Type_handler *type_handler() const override
  { return &amp;type_handler_slonglong; }
  my_decimal *val_decimal(my_decimal *) { DBUG_ASSERT(fixed()); return 0; }
};


class Item_func_udf_str :public Item_func
{
public:
  Item_func_udf_str(THD *thd, udf_func *udf_arg):
    Item_func(thd) {}
  Item_func_udf_str(THD *thd, udf_func *udf_arg, List&lt;Item&gt; &amp;list):
    Item_func(thd, list) {}
  String *val_str(String *)
    { DBUG_ASSERT(fixed()); null_value=1; return 0; }
  double val_real() { DBUG_ASSERT(fixed()); null_value= 1; return 0.0; }
  longlong val_int() { DBUG_ASSERT(fixed()); null_value=1; return 0; }
  bool fix_length_and_dec(THD *thd) override
  { base_flags|= item_base_t::MAYBE_NULL; max_length=0; return FALSE; }
};

#endif /* HAVE_DLOPEN */

void mysql_ull_cleanup(THD *thd);
void mysql_ull_set_explicit_lock_duration(THD *thd);


class Item_func_lock :public Item_long_func
{
 public:
  Item_func_lock(THD *thd): Item_long_func(thd) { }
  Item_func_lock(THD *thd, Item *a): Item_long_func(thd, a) {}
  Item_func_lock(THD *thd, Item *a, Item *b): Item_long_func(thd, a, b) {}
  table_map used_tables() const override
  {
    return used_tables_cache | RAND_TABLE_BIT;
  }
  bool const_item() const override { return 0; }
  bool is_expensive() override { return 1; }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
};


class Item_func_get_lock final :public Item_func_lock
{
  bool check_arguments() const override
  {
    return args[0]-&gt;check_type_general_purpose_string(func_name_cstring()) ||
           args[1]-&gt;check_type_can_return_real(func_name_cstring());
  }
  String value;
 public:
  Item_func_get_lock(THD *thd, Item *a, Item *b) :Item_func_lock(thd, a, b) {}
  longlong val_int() override final;
  LEX_CSTRING func_name_cstring() const override final
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;get_lock&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    max_length= 1;
    set_maybe_null();
    return FALSE;
  }
protected:
  Item *shallow_copy(THD *thd) const override final
  { return get_item_copy&lt;Item_func_get_lock&gt;(thd, this); }
};


class Item_func_release_all_locks final :public Item_func_lock
{
public:
  Item_func_release_all_locks(THD *thd): Item_func_lock(thd)
  { unsigned_flag= 1; }
  longlong val_int() override final;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;release_all_locks&quot;) };
    return name;
  }
protected:
  Item *shallow_copy(THD *thd) const override final
  { return get_item_copy&lt;Item_func_release_all_locks&gt;(thd, this); }
};


class Item_func_release_lock final :public Item_func_lock
{
  bool check_arguments() const override
  { return args[0]-&gt;check_type_general_purpose_string(func_name_cstring()); }
  String value;
public:
  Item_func_release_lock(THD *thd, Item *a): Item_func_lock(thd, a) {}
  longlong val_int() override final;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;release_lock&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    max_length= 1;
    set_maybe_null();
    return FALSE;
  }
protected:
  Item *shallow_copy(THD *thd) const override final
  { return get_item_copy&lt;Item_func_release_lock&gt;(thd, this); }
};


/* replication functions */

class Item_master_pos_wait :public Item_longlong_func
{
  bool check_arguments() const override
  {
    return
      args[0]-&gt;check_type_general_purpose_string(func_name_cstring()) ||
      args[1]-&gt;check_type_can_return_int(func_name_cstring()) ||
      (arg_count &gt; 2 &amp;&amp; args[2]-&gt;check_type_can_return_int(func_name_cstring())) ||
      (arg_count &gt; 3 &amp;&amp; args[3]-&gt;check_type_general_purpose_string(func_name_cstring()));
  }
  String value;
public:
  Item_master_pos_wait(THD *thd, Item *a, Item *b)
   :Item_longlong_func(thd, a, b) {}
  Item_master_pos_wait(THD *thd, Item *a, Item *b, Item *c):
    Item_longlong_func(thd, a, b, c) {}
  Item_master_pos_wait(THD *thd, Item *a, Item *b, Item *c, Item *d):
    Item_longlong_func(thd, a, b, c, d) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;master_pos_wait&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    max_length=21;
    set_maybe_null();
    return FALSE;
  }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_master_pos_wait&gt;(thd, this); }
};


class Item_master_gtid_wait :public Item_long_func
{
  bool check_arguments() const override
  {
    return args[0]-&gt;check_type_general_purpose_string(func_name_cstring()) ||
      (arg_count &gt; 1 &amp;&amp; args[1]-&gt;check_type_can_return_real(func_name_cstring()));
  }
  String value;
public:
  Item_master_gtid_wait(THD *thd, Item *a)
   :Item_long_func(thd, a) {}
  Item_master_gtid_wait(THD *thd, Item *a, Item *b)
   :Item_long_func(thd, a, b) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;master_gtid_wait&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override { max_length=2; return FALSE; }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_master_gtid_wait&gt;(thd, this); }
};


/* Handling of user definable variables */

class user_var_entry;


/**
  A class to set and get user variables
*/
class Item_func_user_var :public Item_hybrid_func
{
protected:
  user_var_entry *m_var_entry;
public:
  LEX_CSTRING name; // keep it public
  Item_func_user_var(THD *thd, const LEX_CSTRING *a)
    :Item_hybrid_func(thd), m_var_entry(NULL), name(*a) { }
  Item_func_user_var(THD *thd, const LEX_CSTRING *a, Item *b)
    :Item_hybrid_func(thd, b), m_var_entry(NULL), name(*a) { }
  Item_func_user_var(THD *thd, Item_func_user_var *item)
    :Item_hybrid_func(thd, item),
    m_var_entry(item-&gt;m_var_entry), name(item-&gt;name) { }
  Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src,
                             const Tmp_field_param *param) override
  {
    DBUG_ASSERT(fixed());
    return create_tmp_field_ex_from_handler(root, table, src, param,
                                            type_handler());
  }
  Field *create_field_for_create_select(MEM_ROOT *root, TABLE *table) override
  { return create_table_field_from_handler(root, table); }
  bool check_vcol_func_processor(void *arg) override;
  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override
  {
    return type_handler()-&gt;Item_get_date_with_warn(thd, this, ltime, fuzzydate);
  }
};


class Item_func_set_user_var :public Item_func_user_var
{
  /*
    The entry_thread_id variable is used:
    1) to skip unnecessary updates of the entry field (see above);
    2) to reset the entry field that was initialized in the other thread
       (for example, an item tree of a trigger that updates user variables
       may be shared between several connections, and the entry_thread_id field
       prevents updates of one connection user variables from a concurrent
       connection calling the same trigger that initially updated some
       user variable it the first connection context).
  */
  my_thread_id entry_thread_id;
  String value;
  my_decimal decimal_buff;
  bool null_item;
  union
  {
    longlong vint;
    double vreal;
    String *vstr;
    my_decimal *vdec;
  } save_result;

public:
  Item_func_set_user_var(THD *thd, const LEX_CSTRING *a, Item *b):
    Item_func_user_var(thd, a, b),
    entry_thread_id(0)
  {}
  Item_func_set_user_var(THD *thd, Item_func_set_user_var *item)
    :Item_func_user_var(thd, item),
    entry_thread_id(item-&gt;entry_thread_id),
    value(item-&gt;value), decimal_buff(item-&gt;decimal_buff),
    null_item(item-&gt;null_item), save_result(item-&gt;save_result)
  {}

  enum Functype functype() const override { return SUSERVAR_FUNC; }
  double val_real() override;
  longlong val_int() override;
  String *val_str(String *str) override;
  my_decimal *val_decimal(my_decimal *) override;
  double val_result() override;
  longlong val_int_result() override;
  bool val_bool_result() override;
  String *str_result(String *str) override;
  my_decimal *val_decimal_result(my_decimal *) override;
  bool is_null_result() override;
  bool update_hash(void *ptr, size_t length, const Type_handler *th,
                   CHARSET_INFO *cs);
  bool send(Protocol *protocol, st_value *buffer) override;
  void make_send_field(THD *thd, Send_field *tmp_field) override;
  bool check(bool use_result_field);
  void save_item_result(Item *item);
  bool update();
  bool fix_fields(THD *thd, Item **ref) override;
  bool fix_length_and_dec(THD *thd) override;
  void print(String *str, enum_query_type query_type) override;
  enum precedence precedence() const override { return ASSIGN_PRECEDENCE; }
  void print_as_stmt(String *str, enum_query_type query_type);
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;set_user_var&quot;) };
    return name;
  }
  int save_in_field(Field *field, bool no_conversions,
                    bool can_use_result_field);
  int save_in_field(Field *field, bool no_conversions) override
  {
    return save_in_field(field, no_conversions, 1);
  }
  void save_org_in_field(Field *field,
                         fast_field_copier data __attribute__ ((__unused__)))
    override
  { (void) save_in_field(field, 1, 0); }
  bool register_field_in_read_map(void *arg) override;
  bool register_field_in_bitmap(void *arg) override;
  bool set_entry(THD *thd, bool create_if_not_exists);
  void cleanup() override;
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_set_user_var&gt;(thd, this); }
public:
  bool excl_dep_on_table(table_map tab_map) override { return false; }
};


class Item_func_get_user_var :public Item_func_user_var,
                              private Settable_routine_parameter
{
public:
  Item_func_get_user_var(THD *thd, const LEX_CSTRING *a):
    Item_func_user_var(thd, a) {}
  enum Functype functype() const override { return GUSERVAR_FUNC; }
  LEX_CSTRING get_name() { return name; }
  double val_real() override;
  longlong val_int() override;
  my_decimal *val_decimal(my_decimal*) override;
  String *val_str(String* str) override;
  bool fix_length_and_dec(THD *thd) override;
  void print(String *str, enum_query_type query_type) override;
  /*
    We must always return variables as strings to guard against selects of type
    select @t1:=1,@t1,@t:=&quot;hello&quot;,@t from foo where (@t1:= t2.b)
  */
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;get_user_var&quot;) };
    return name;
  }
  bool const_item() const override;
  table_map used_tables() const override
  { return const_item() ? 0 : RAND_TABLE_BIT; }
  bool eq(const Item *item, const Eq_config &amp;config) const override;
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_get_user_var&gt;(thd, this); }
private:
  bool set_value(THD *thd, sp_rcontext *ctx, Item **it) override;

public:
  Settable_routine_parameter *get_settable_routine_parameter() override
  {
    return this;
  }
};


/*
  This item represents user variable used as out parameter (e.g in LOAD DATA),
  and it is supposed to be used only for this purprose. So it is simplified
  a lot. Actually you should never obtain its value.

  The only two reasons for this thing being an Item is possibility to store it
  in List&lt;Item&gt; and desire to place this code somewhere near other functions
  working with user variables.
*/
class Item_user_var_as_out_param :public Item_fixed_hybrid,
                                  public Load_data_outvar
{
  LEX_CSTRING org_name;
  user_var_entry *entry;
public:
  Item_user_var_as_out_param(THD *thd, const LEX_CSTRING *a)
  :Item_fixed_hybrid(thd)
  {
    DBUG_ASSERT(a-&gt;length &lt; UINT_MAX32);
    org_name= *a;
    set_name(thd, a-&gt;str, a-&gt;length, system_charset_info);
  }
  Load_data_outvar *get_load_data_outvar() override
  {
    return this;
  }
  bool load_data_set_null(THD *thd, const Load_data_param *param) override
  {
    set_null_value(param-&gt;charset());
    return false;
  }
  bool load_data_set_no_data(THD *thd, const Load_data_param *param) override
  {
    set_null_value(param-&gt;charset());
    return false;
  }
  bool load_data_set_value(THD *thd, const char *pos, uint length,
                           const Load_data_param *param) override
  {
    set_value(pos, length, param-&gt;charset());
    return false;
  }
  void load_data_print_for_log_event(THD *thd, String *to) const override;
  bool load_data_add_outvar(THD *thd, Load_data_param *param) const override
  {
    return param-&gt;add_outvar_user_var(thd);
  }
  uint load_data_fixed_length() const override
  {
    return 0;
  }
  Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src,
                             const Tmp_field_param *param) override
  {
    DBUG_ASSERT(0);
    return NULL;
  }
  /* We should return something different from FIELD_ITEM here */
  enum Type type() const override { return CONST_ITEM;}
  double val_real() override;
  longlong val_int() override;
  String *val_str(String *str) override;
  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override;
  my_decimal *val_decimal(my_decimal *decimal_buffer) override;
  /* fix_fields() binds variable name with its entry structure */
  bool fix_fields(THD *thd, Item **ref) override;
  void set_null_value(CHARSET_INFO* cs);
  void set_value(const char *str, uint length, CHARSET_INFO* cs);
  const Type_handler *type_handler() const override
  { return &amp;type_handler_double; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_user_var_as_out_param&gt;(thd, this); }
  Item *deep_copy(THD *thd) const override
  { return shallow_copy_with_checks(thd); }
};


/* A system variable */

#define GET_SYS_VAR_CACHE_LONG     1
#define GET_SYS_VAR_CACHE_DOUBLE   2
#define GET_SYS_VAR_CACHE_STRING   4

class Item_func_get_system_var :public Item_func
{
  sys_var *var;
  enum_var_type var_type, orig_var_type;
  LEX_CSTRING component;
  longlong cached_llval;
  double cached_dval;
  String cached_strval;
  bool cached_null_value;
  query_id_t used_query_id;
  uchar cache_present;

public:
  Item_func_get_system_var(THD *thd, sys_var *var_arg,
                           enum_var_type var_type_arg,
                           LEX_CSTRING *component_arg, const char *name_arg,
                           size_t name_len_arg);
  enum Functype functype() const override { return GSYSVAR_FUNC; }
  void update_null_value() override;
  bool fix_length_and_dec(THD *thd) override;
  void print(String *str, enum_query_type query_type) override;
  bool const_item() const override { return true; }
  table_map used_tables() const override { return 0; }
  const Type_handler *type_handler() const override;
  double val_real() override;
  longlong val_int() override;
  String* val_str(String*) override;
  my_decimal *val_decimal(my_decimal *dec_buf) override
  { return val_decimal_from_real(dec_buf); }
  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override
  {
    return type_handler()-&gt;Item_get_date_with_warn(thd, this, ltime, fuzzydate);
  }
  /* TODO: fix to support views */
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;get_system_var&quot;) };
    return name;
  }
  /**
    Indicates whether this system variable is written to the binlog or not.

    Variables are written to the binlog as part of &quot;status_vars&quot; in
    Query_log_event, as an Intvar_log_event, or a Rand_log_event.

    @return true if the variable is written to the binlog, false otherwise.
  */
  bool is_written_to_binlog();
  bool eq(const Item *item, const Eq_config &amp;config) const override;

  void cleanup() override;
  bool check_vcol_func_processor(void *arg) override;
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_get_system_var&gt;(thd, this); }
};


/* for fulltext search */

class Item_func_match :public Item_real_func
{
public:
  uint key, match_flags;
  bool join_key;
  DTCollation cmp_collation;
  FT_INFO *ft_handler;
  TABLE *table;
  Item_func_match *master;   // for master-slave optimization
  Item *concat_ws;           // Item_func_concat_ws
  String value;              // value of concat_ws
  String search_value;       // key_item()&#039;s value converted to cmp_collation

  Item_func_match(THD *thd, List&lt;Item&gt; &amp;a, uint b):
    Item_real_func(thd, a), key(0), match_flags(b), join_key(0), ft_handler(0),
    table(0), master(0), concat_ws(0) { }
  void cleanup() override
  {
    DBUG_ENTER(&quot;Item_func_match::cleanup&quot;);
    Item_real_func::cleanup();
    if (!master &amp;&amp; ft_handler)
      ft_handler-&gt;please-&gt;close_search(ft_handler);
    ft_handler= 0;
    concat_ws= 0;
    table= 0;           // required by Item_func_match::eq()
    DBUG_VOID_RETURN;
  }
  bool is_expensive_processor(void *arg) override { return TRUE; }
  enum Functype functype() const override { return FT_FUNC; }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;match&quot;) };
    return name;
  }
  bool eval_not_null_tables(void *opt_arg) override
  {
    not_null_tables_cache= 0;
    return 0;
  }
  bool find_not_null_fields(table_map allowed) override
  {
    return false;
  }
  bool fix_fields(THD *thd, Item **ref) override;
  bool eq(const Item *, const Eq_config &amp;config) const override;
  /* The following should be safe, even if we compare doubles */
  longlong val_int() override { DBUG_ASSERT(fixed()); return val_real() != 0.0; }
  double val_real() override;
  void print(String *str, enum_query_type query_type) override;

  bool fix_index();
  bool init_search(THD *thd, bool no_order);
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(&quot;match ... against()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_match&gt;(thd, this); }
  Item *deep_copy(THD *thd) const override { return nullptr; }
private:
  /**
     Check whether storage engine for given table, 
     allows FTS Boolean search on non-indexed columns.

     @todo A flag should be added to the extended fulltext API so that 
           it may be checked whether search on non-indexed columns are 
           supported. Currently, it is not possible to check for such a 
           flag since @c this-&gt;ft_handler is not yet set when this function is 
           called.  The current hack is to assume that search on non-indexed
           columns are supported for engines that does not support the extended
           fulltext API (e.g., MyISAM), while it is not supported for other 
           engines (e.g., InnoDB)

     @param table_arg Table for which storage engine to check

     @retval true if BOOLEAN search on non-indexed columns is supported
     @retval false otherwise
   */
  bool allows_search_on_non_indexed_columns(TABLE* table_arg)
  {
    // Only Boolean search may support non_indexed columns
    if (!(match_flags &amp; FT_BOOL))
      return false;

    DBUG_ASSERT(table_arg &amp;&amp; table_arg-&gt;file);

    // Assume that if extended fulltext API is not supported,
    // non-indexed columns are allowed.  This will be true for MyISAM.
    if ((table_arg-&gt;file-&gt;ha_table_flags() &amp; HA_CAN_FULLTEXT_EXT) == 0)
      return true;

    return false;
  }
};


class Item_func_bit_xor : public Item_func_bit_operator
{
public:
  Item_func_bit_xor(THD *thd, Item *a, Item *b)
   :Item_func_bit_operator(thd, a, b) {}
  bool fix_length_and_dec(THD *thd) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;^&quot;) };
    return name;
  }
  enum precedence precedence() const override { return BITXOR_PRECEDENCE; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_bit_xor&gt;(thd, this); }
};

class Item_func_is_free_lock :public Item_long_func
{
  bool check_arguments() const override
  { return args[0]-&gt;check_type_general_purpose_string(func_name_cstring()); }
  String value;
public:
  Item_func_is_free_lock(THD *thd, Item *a): Item_long_func(thd, a) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;is_free_lock&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    decimals=0;
    max_length=1;
    set_maybe_null();
    return FALSE;
  }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_is_free_lock&gt;(thd, this); }
};

class Item_func_is_used_lock :public Item_long_func
{
  bool check_arguments() const override
  { return args[0]-&gt;check_type_general_purpose_string(func_name_cstring()); }
  String value;
public:
  Item_func_is_used_lock(THD *thd, Item *a): Item_long_func(thd, a) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;is_used_lock&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    decimals=0; max_length=10;
    set_maybe_null();
    return FALSE;
  }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_is_used_lock&gt;(thd, this); }
};


struct Lex_cast_type_st: public Lex_length_and_dec_st
{
private:
  const Type_handler *m_type_handler;
  CHARSET_INFO *m_charset;
public:
  void set(const Type_handler *handler,
           Lex_length_and_dec_st length_and_dec,
           CHARSET_INFO *cs= NULL)
  {
    m_type_handler= handler;
    m_charset= cs;
    Lex_length_and_dec_st::operator=(length_and_dec);
  }
  bool set(const Type_handler *handler,
           const Lex_length_and_dec_st &amp; length_and_dec,
           const Lex_column_charset_collation_attrs_st &amp;cscl,
           CHARSET_INFO *defcs)
  {
    CHARSET_INFO *tmp= cscl.resolved_to_character_set(defcs);
    if (!tmp)
      return true;
    set(handler, length_and_dec, tmp);
    return false;
  }
  void set(const Type_handler *handler)
  {
    m_type_handler= handler;
    m_charset= NULL;
    Lex_length_and_dec_st::reset();
  }
  const Type_handler *type_handler() const { return m_type_handler; }
  CHARSET_INFO *charset() const { return m_charset; }
  Item *create_typecast_item(THD *thd, Item *item) const
  {
    return m_type_handler-&gt;
      create_typecast_item(thd, item, Type_cast_attributes(*this, m_charset));
  }
  Item *create_typecast_item_or_error(THD *thd, Item *item) const;
};


class Item_func_row_count :public Item_longlong_func
{
public:
  Item_func_row_count(THD *thd): Item_longlong_func(thd) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;row_count&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    decimals= 0;
    base_flags&amp;= ~item_base_t::MAYBE_NULL;
    return FALSE;
  }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_row_count&gt;(thd, this); }
};


/*
 *
 * Stored FUNCTIONs
 *
 */

class Item_func_sp :public Item_func,
                    public Item_sp
{
private:
  const Sp_handler *m_handler;

  bool execute();

protected:
  bool is_expensive_processor(void *arg) override
  { return is_expensive(); }

  bool check_arguments() const override
  {
    // sp_prepare_func_item() checks that the number of columns is correct
    return false;
  } 
public:

  Item_func_sp(THD *thd, Name_resolution_context *context_arg,
               sp_name *name, const Sp_handler *sph);

  Item_func_sp(THD *thd, Name_resolution_context *context_arg,
               sp_name *name, const Sp_handler *sph, List&lt;Item&gt; &amp;list);

  virtual ~Item_func_sp() = default;

  void update_used_tables() override;

  void cleanup() override;

  LEX_CSTRING func_name_cstring() const override;

  const Type_handler *type_handler() const override;

  Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src,
                             const Tmp_field_param *param) override;
  Field *create_field_for_create_select(MEM_ROOT *root, TABLE *table) override
  {
    return result_type() != STRING_RESULT ?
           sp_result_field :
           create_table_field_from_handler(root, table);
  }
  void make_send_field(THD *thd, Send_field *tmp_field) override;

  longlong val_int() override
  {
    if (execute())
      return (longlong) 0;
    return sp_result_field-&gt;val_int();
  }

  double val_real() override
  {
    if (execute())
      return 0.0;
    return sp_result_field-&gt;val_real();
  }

  my_decimal *val_decimal(my_decimal *dec_buf) override
  {
    if (execute())
      return NULL;
    return sp_result_field-&gt;val_decimal(dec_buf);
  }

  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override
  {
    if (execute())
      return true;
    return sp_result_field-&gt;get_date(ltime, fuzzydate);
  }

  String *val_str(String *str) override
  {
    String buf;
    char buff[20];
    buf.set(buff, 20, str-&gt;charset());
    buf.length(0);
    if (execute())
      return NULL;
    /*
      result_field will set buf pointing to internal buffer
      of the resul_field. Due to this it will change any time
      when SP is executed. In order to prevent occasional
      corruption of returned value, we make here a copy.
    */
    sp_result_field-&gt;val_str(&amp;buf);
    str-&gt;copy(buf);
    return str;
  }

  bool val_native(THD *thd, Native *to) override
  {
    if (execute())
      return true;
    return (null_value= sp_result_field-&gt;val_native(to));
  }

  void update_null_value() override
  { 
    execute();
  }

  bool change_context_processor(void *cntx) override
  { context= (Name_resolution_context *)cntx; return FALSE; }

  enum Functype functype() const override { return FUNC_SP; }

  bool fix_fields(THD *thd, Item **ref) override;
  bool fix_length_and_dec(THD *thd) override;
  bool is_expensive() override;

  inline Field *get_sp_result_field()
  {
    return sp_result_field;
  }
  const sp_name *get_sp_name() const
  {
    return m_name;
  }

  bool check_vcol_func_processor(void *arg) override;
  bool limit_index_condition_pushdown_processor(void *opt_arg) override
  {
    return TRUE;
  }
protected:
  Item *shallow_copy(THD *thd) const override { return 0; }
public:
  bool eval_not_null_tables(void *opt_arg) override
  {
    not_null_tables_cache= 0;
    return 0;
  }
  bool excl_dep_on_grouping_fields(st_select_lex *sel) override
  { return false; }
  bool find_not_null_fields(table_map allowed) override
  {
    return false;
  }
};


class Item_func_found_rows :public Item_longlong_func
{
public:
  Item_func_found_rows(THD *thd): Item_longlong_func(thd) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;found_rows&quot;) };
    return name;
  }
  bool fix_length_and_dec(THD *thd) override
  {
    decimals= 0;
    base_flags&amp;= ~item_base_t::MAYBE_NULL;
    return FALSE;
  }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_found_rows&gt;(thd, this); }
};


class Item_func_oracle_sql_rowcount :public Item_longlong_func
{
public:
  Item_func_oracle_sql_rowcount(THD *thd): Item_longlong_func(thd) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;SQL%ROWCOUNT&quot;) };
    return name;
  }
  void print(String *str, enum_query_type query_type) override
  {
    str-&gt;append(func_name_cstring());
  }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_oracle_sql_rowcount&gt;(thd, this); }
};


class Item_func_sqlcode: public Item_long_func
{
public:
  Item_func_sqlcode(THD *thd): Item_long_func(thd) { }
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;SQLCODE&quot;) };
    return name;
  }
  void print(String *str, enum_query_type query_type) override
  {
    str-&gt;append(func_name_cstring());
  }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_IMPOSSIBLE);
  }
  bool fix_length_and_dec(THD *thd) override
  {
    base_flags&amp;= ~item_base_t::MAYBE_NULL;
    null_value= false;
    max_length= 11;
    return FALSE;
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_sqlcode&gt;(thd, this); }
};


void uuid_short_init();
ulonglong server_uuid_value();

class Item_func_uuid_short :public Item_longlong_func
{
public:
  Item_func_uuid_short(THD *thd): Item_longlong_func(thd) {}
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;uuid_short&quot;) };
    return name;
  }
  longlong val_int() override;
  bool const_item() const override { return false; }
  bool fix_length_and_dec(THD *thd) override
  { max_length= 21; unsigned_flag=1; return FALSE; }
  table_map used_tables() const override { return RAND_TABLE_BIT; }
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg,
                                     VCOL_NON_DETERMINISTIC);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_uuid_short&gt;(thd, this); }
};


class Item_func_last_value :public Item_func
{
protected:
  Item *last_value;
public:
  Item_func_last_value(THD *thd, List&lt;Item&gt; &amp;list): Item_func(thd, list) {}
  double val_real() override;
  longlong val_int() override;
  String *val_str(String *) override;
  my_decimal *val_decimal(my_decimal *) override;
  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override;
  bool val_native(THD *thd, Native *) override;
  bool fix_length_and_dec(THD *thd) override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;last_value&quot;) };
    return name;
  }
  const Type_handler *type_handler() const override
  { return last_value-&gt;type_handler(); }
  bool eval_not_null_tables(void *) override
  {
    not_null_tables_cache= 0;
    return 0;
  }
  bool find_not_null_fields(table_map allowed) override
  {
    return false;
  }
  bool const_item() const override { return 0; }
  void evaluate_sideeffects();
  void update_used_tables() override
  {
    Item_func::update_used_tables();
    copy_flags(last_value, item_base_t::MAYBE_NULL);
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_last_value&gt;(thd, this); }
};


/* Implementation for sequences: NEXT VALUE FOR sequence and NEXTVAL() */

class Item_func_nextval :public Item_longlong_func
{
protected:
  TABLE_LIST *table_list;
  TABLE *table;
  bool check_access(THD *, privilege_t);
public:
  Item_func_nextval(THD *thd, TABLE_LIST *table_list_arg):
  Item_longlong_func(thd), table_list(table_list_arg), table(0) {}
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;nextval&quot;) };
    return name;
  }
  bool fix_fields(THD *thd, Item **ref) override
  {
    /* Don&#039;t check privileges, if it&#039;s parse_vcol_defs() */
    return (table_list-&gt;table &amp;&amp; check_sequence_privileges(thd)) ||
           Item_longlong_func::fix_fields(thd, ref);
  }
  bool check_sequence_privileges(void *thd) override
  { return check_access((THD*)thd, INSERT_ACL | SELECT_ACL); }
  bool fix_length_and_dec(THD *thd) override
  {
    unsigned_flag= 0;
    max_length= MAX_BIGINT_WIDTH;
    set_maybe_null();             /* In case of errors */
    return FALSE;
  }
  /*
    update_table() function must be called during the value function
    as in case of DEFAULT the sequence table may not yet be open
    while fix_fields() are called
  */
  void update_table()
  {
    table= table_list-&gt;table;
    DBUG_ASSERT(table);
  }
  bool const_item() const override { return 0; }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_nextval&gt;(thd, this); }
public:
  void print(String *str, enum_query_type query_type) override;
  bool check_vcol_func_processor(void *arg) override
  {
    return mark_unsupported_function(func_name(), &quot;()&quot;, arg, VCOL_NEXTVAL);
  }
};


/* Implementation for sequences: LASTVAL(sequence), PostgreSQL style */

class Item_func_lastval :public Item_func_nextval
{
public:
  Item_func_lastval(THD *thd, TABLE_LIST *table_list_arg):
  Item_func_nextval(thd, table_list_arg) {}
  bool check_sequence_privileges(void *thd) override
  { return check_access((THD*)thd, SELECT_ACL); }
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;lastval&quot;) };
    return name;
  }
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_lastval&gt;(thd, this); }
};


/* Implementation for sequences: SETVAL(sequence), PostgreSQL style */

class Item_func_setval :public Item_func_nextval
{
  longlong nextval;
  ulonglong round;
  bool is_used;
public:
  Item_func_setval(THD *thd, TABLE_LIST *table_list_arg, longlong nextval_arg,
                   ulonglong round_arg, bool is_used_arg)
    : Item_func_nextval(thd, table_list_arg),
    nextval(nextval_arg), round(round_arg), is_used(is_used_arg)
  {}
  bool check_sequence_privileges(void *thd) override
  { return check_access((THD*)thd, INSERT_ACL); }
  longlong val_int() override;
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN(&quot;setval&quot;) };
    return name;
  }
  void print(String *str, enum_query_type query_type) override;
protected:
  Item *shallow_copy(THD *thd) const override
  { return get_item_copy&lt;Item_func_setval&gt;(thd, this); }
};

class Interruptible_wait;

Item *get_system_var(THD *thd, enum_var_type var_type,
                     const LEX_CSTRING *name, const LEX_CSTRING *component);
extern bool check_reserved_words(const LEX_CSTRING *name);
double my_double_round(double value, longlong dec, bool dec_unsigned,
                       bool truncate);

extern bool volatile  mqh_used;

bool update_hash(user_var_entry *entry, bool set_null, void *ptr, size_t length,
                 const Type_handler *th, CHARSET_INFO *cs);

#endif /* ITEM_FUNC_INCLUDED */
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