#include <sys/types.h>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <memory>
#include <new>
#include <optional>
#include <string>
#include <type_traits>
#include <vector>
#include "decimal.h"
#include "field_types.h"
#include "lex_string.h"
#include "memory_debugging.h"
#include "my_alloc.h"
#include "my_bitmap.h"
#include "my_compiler.h"
#include "my_dbug.h"
#include "my_double2ulonglong.h"
#include "my_inttypes.h"
#include "my_sys.h"
#include "my_table_map.h"
#include "my_time.h"
#include "mysql/strings/dtoa.h"
#include "mysql/strings/m_ctype.h"
#include "mysql/strings/my_strtoll10.h"
#include "mysql/udf_registration_types.h"
#include "mysql_com.h"
#include "mysql_time.h"
#include "mysqld_error.h"
#include "nulls.h"
#include "sql-common/my_decimal.h"
#include "sql/auth/auth_acls.h"
#include "sql/enum_query_type.h"
#include "sql/field.h"
#include "sql/mem_root_array.h"
#include "sql/parse_location.h"
#include "sql/parse_tree_node_base.h"
#include "sql/sql_array.h"
#include "sql/sql_const.h"
#include "sql/sql_list.h"
#include "sql/table.h"
#include "sql/table_trigger_field_support.h"
#include "sql/thr_malloc.h"
#include "sql/trigger_def.h"
#include "sql_string.h"
#include "string_with_len.h"
#include "template_utils.h"

Classes
class	DTCollation

class	Mark_field
	Class used as argument to Item::walk() together with mark_field_in_map() More...

class	Used_tables
	Class used as argument to Item::walk() together with used_tables_for_level() More...

class	Name_string
	Storage for name strings. More...

class	Item_name_string
	Storage for Item names. More...

struct	Name_resolution_context

struct	Check_function_as_value_generator_parameters
	Struct used to pass around arguments to/from check_function_as_value_generator. More...

class	Name_resolution_context_state

class	Bool3
	A type for SQL-like 3-valued Booleans: true/false/unknown. More...

class	Type_properties
	Type properties, used to collect type information for later assignment to an Item object. More...

class	Settable_routine_parameter

class	Item_tree_walker
	Utility mixin class to be able to walk() only parts of item trees. More...

class	CostOfItem
	This class represents the cost of evaluating an Item. More...

struct	ContainedSubquery
	This class represents a subquery contained in some subclass of Item_subselect,. More...

class	Item
	Base class that is used to represent any kind of expression in a relational query. More...

class	Item::Collect_item_fields_or_refs

class	Item::Collect_item_fields_or_view_refs

class	Item::Cleanup_after_removal_context
	Context object for (functions that override) Item::clean_up_after_removal(). More...

struct	Item::Css_info
	Minion class under Collect_scalar_subquery_info. More...

struct	Item::Collect_scalar_subquery_info
	Context struct used by walk method collect_scalar_subqueries to accumulate information about scalar subqueries found. More...

struct	Item::Replace_equal

struct	Item::Item_replacement

struct	Item::Item_field_replacement

struct	Item::Item_func_call_replacement

struct	Item::Item_view_ref_replacement

struct	Item::Aggregate_replacement

struct	Item::Aggregate_ref_update

struct	cache_const_expr_arg
	Descriptor of what and how to cache for Item::cache_const_expr_transformer/analyzer. More...

class	Item_basic_constant

class	Item_sp_variable

class	Item_splocal

class	Item_case_expr

class	Item_name_const

class	Item_num

class	Item_ident

struct	Item_ident::Change_context
	< Argument object to change_context_processor More...

struct	Item_ident::Depended_change
	Argument structure for walk processor Item::update_depended_from. More...

class	Item_ident_for_show

class	Item_field

class	Item_asterisk
	Represents [schema. More...

class	Item_null

class	Item_param
	Dynamic parameters used as placeholders ('?') inside prepared statements. More...

class	Item_int

class	Item_int_0
	Item_int with value==0 and length==1. More...

class	Item_temporal

class	Item_uint

class	Item_decimal

class	Item_float

class	Item_func_pi

class	Item_string

class	Item_static_string_func

class	Item_partition_func_safe_string

class	Item_blob

class	Item_empty_string
	Item_empty_string – is a utility class to put an item into List<Item> which is then used in protocol.send_result_set_metadata() when sending SHOW output to the client. More...

class	Item_return_int

class	Item_hex_string

class	Item_bin_string

class	Item_result_field
	Item with result field. More...

class	Item_ref

class	Item_view_ref
	Class for fields from derived tables and views. More...

class	Item_outer_ref

class	Item_ref_null_helper

class	Item_int_with_ref

class	Item_temporal_with_ref

class	Item_datetime_with_ref

class	Item_time_with_ref

class	Item_metadata_copy
	A dummy item that contains a copy/backup of the given Item's metadata; not valid for data. More...

class	Cached_item
	This is used for segregating rows in groups (e.g. More...

class	Cached_item_str

class	Cached_item_json
	Cached_item subclass for JSON values. More...

class	Cached_item_real

class	Cached_item_int

class	Cached_item_temporal

class	Cached_item_decimal

class	Item_default_value

class	Item_insert_value

class	Item_trigger_field
	Represents NEW/OLD version of field of row which is changed/read in trigger. More...

class	Item_cache

class	Item_cache_int

class	Item_cache_bit
	Cache class for BIT type expressions. More...

class	Item_cache_real

class	Item_cache_decimal

class	Item_cache_str

class	Item_cache_row

class	Item_cache_datetime

class	Item_cache_json
	An item cache for values of type JSON. More...

class	Item_aggregate_type
	Interface for storing an aggregation of type and type specification of multiple Item objects. More...

class	Item_type_holder
	Item_type_holder stores an aggregation of name, type and type specification of UNIONS and derived tables. More...

class	Item_values_column
	Reference item that encapsulates both the type and the contained items of a single column of a VALUES ROW query expression. More...

class	Item_json
	A class that represents a constant JSON value. More...

Macros
#define	MY_COLL_ALLOW_SUPERSET_CONV 1

#define	MY_COLL_ALLOW_COERCIBLE_CONV 2

#define	MY_COLL_DISALLOW_NONE 4

#define	MY_COLL_ALLOW_NUMERIC_CONV 8

#define	MY_COLL_ALLOW_CONV (MY_COLL_ALLOW_SUPERSET_CONV \| MY_COLL_ALLOW_COERCIBLE_CONV)

#define	MY_COLL_CMP_CONV (MY_COLL_ALLOW_CONV \| MY_COLL_DISALLOW_NONE)

#define	NAME_STRING(x) Name_string(STRING_WITH_LEN(x))

Typedefs
typedef Bounds_checked_array< Item * >	Ref_item_array

typedef enum monotonicity_info	enum_monotonicity_info

typedef bool(Item::*	Item_analyzer) (uchar **argp)

typedef Item (Item::	Item_transformer) (uchar *arg)
	Type for transformers used by Item::transform and Item::compile. More...

typedef void(*	Cond_traverser) (const Item item, void arg)

Enumerations
enum	monotonicity_info { NON_MONOTONIC , MONOTONIC_INCREASING , MONOTONIC_INCREASING_NOT_NULL , MONOTONIC_STRICT_INCREASING , MONOTONIC_STRICT_INCREASING_NOT_NULL }

Functions
void	item_init (void)
	Init all special items. More...

static uint32	char_to_byte_length_safe (uint32 char_length_arg, uint32 mbmaxlen_arg)

Item_result	numeric_context_result_type (enum_field_types data_type, Item_result result_type, uint8 decimals)

template<typename T >
void	SafeIncrement (T *num)
	Increment *num if it is less than its maximal value. More...

template<class T >
bool	WalkItem (Item *item, enum_walk walk, T &&functor)
	A helper class to give in a functor to Item::walk(). More...

template<class T >
bool	WalkItem (const Item *item, enum_walk walk, T &&functor)
	Overload for const 'item' and functor taking 'const Item*' argument. More...

template<class T , class U >
Item *	CompileItem (Item *item, T &&analyzer, U &&transformer)
	Same as WalkItem, but for Item::compile(). More...

template<class T >
Item *	TransformItem (Item *item, T &&transformer)
	Same as WalkItem, but for Item::transform(). More...

bool	agg_item_collations_for_comparison (DTCollation &c, const char name, Item *items, uint nitems, uint flags)

bool	agg_item_set_converter (DTCollation &coll, const char fname, Item *args, uint nargs, uint flags, int item_sep, bool only_consts)

bool	agg_item_charsets (DTCollation &c, const char name, Item *items, uint nitems, uint flags, int item_sep, bool only_consts)

bool	agg_item_charsets_for_string_result (DTCollation &c, const char name, Item *items, uint nitems, int item_sep=1)

bool	agg_item_charsets_for_comparison (DTCollation &c, const char name, Item *items, uint nitems, int item_sep=1)

constexpr uint16	NO_FIELD_INDEX ((uint16)(-1))

Item_field *	FindEqualField (Item_field item_field, table_map reachable_tables, bool replace, bool found)

longlong	longlong_from_string_with_check (const CHARSET_INFO cs, const char cptr, const char *end, int unsigned_target)
	Converts a string to a longlong integer, with warnings. More...

double	double_from_string_with_check (const CHARSET_INFO cs, const char cptr, const char *end)

Cached_item *	new_Cached_item (THD thd, Item item)
	Create right type of Cached_item for an item. More...

Item_result	item_cmp_type (Item_result a, Item_result b)

bool	resolve_const_item (THD thd, Item ref, Item cmp_item)
	Substitute a const item with a simpler const item, if possible. More...

int	stored_field_cmp_to_item (THD thd, Field field, Item *item)
	Compare the value stored in field with the expression from the query. More...

bool	is_null_on_empty_table (THD thd, Item_field i)
	Check if the column reference that is currently being resolved, will be set to NULL if its qualifying query returns zero rows. More...

void	convert_and_print (const String from_str, String to_str, const CHARSET_INFO *to_cs)
	Helper method: Convert string to the given charset, then print. More...

std::string	ItemToString (const Item *item)

size_t	CountVisibleFields (const mem_root_deque< Item * > &fields)

size_t	CountHiddenFields (const mem_root_deque< Item * > &fields)

Item *	GetNthVisibleField (const mem_root_deque< Item * > &fields, size_t index)

bool	ItemsAreEqual (const Item a, const Item b, bool binary_cmp)
	Returns true iff the two items are equal, as in a->eq(b), after unwrapping refs and Item_cache objects. More...

bool	AllItemsAreEqual (const Item const a, const Item const b, int num_items, bool binary_cmp)
	Returns true iff all items in the two arrays (which must be of the same size) are equal, as in a->eq(b), after unwrapping refs and Item_cache objects. More...

Variables
constexpr float	COND_FILTER_ALLPASS {1.0f}
	Default condition filtering (selectivity) values used by get_filtering_effect() and friends when better estimates (statistics) are not available for a predicate. More...

constexpr float	COND_FILTER_EQUALITY {0.1f}
	Filtering effect for equalities: col1 = col2. More...

constexpr float	COND_FILTER_INEQUALITY {0.3333f}
	Filtering effect for inequalities: col1 > col2. More...

constexpr float	COND_FILTER_BETWEEN {0.1111f}
	Filtering effect for between: col1 BETWEEN a AND b. More...

constexpr float	COND_FILTER_STALE {-1.0f}
	Value is out-of-date, will need recalculation. More...

constexpr float	COND_FILTER_STALE_NO_CONST {-2.0f}
	A special subcase of the above: More...

const Name_string	null_name_string

const String	my_null_string

Macro Definition Documentation

◆ MY_COLL_ALLOW_COERCIBLE_CONV

#define MY_COLL_ALLOW_COERCIBLE_CONV 2

◆ MY_COLL_ALLOW_CONV

#define MY_COLL_ALLOW_CONV (MY_COLL_ALLOW_SUPERSET_CONV | MY_COLL_ALLOW_COERCIBLE_CONV)

◆ MY_COLL_ALLOW_NUMERIC_CONV

#define MY_COLL_ALLOW_NUMERIC_CONV 8

◆ MY_COLL_ALLOW_SUPERSET_CONV

#define MY_COLL_ALLOW_SUPERSET_CONV 1

◆ MY_COLL_CMP_CONV

#define MY_COLL_CMP_CONV (MY_COLL_ALLOW_CONV | MY_COLL_DISALLOW_NONE)

◆ MY_COLL_DISALLOW_NONE

#define MY_COLL_DISALLOW_NONE 4

◆ NAME_STRING

#define NAME_STRING ( x ) Name_string(STRING_WITH_LEN(x))

Typedef Documentation

◆ Cond_traverser

typedef void(* Cond_traverser) (const Item *item, void *arg)

◆ enum_monotonicity_info

typedef enum monotonicity_info enum_monotonicity_info

◆ Item_analyzer

typedef bool(Item::* Item_analyzer) (uchar **argp)

◆ Item_transformer

typedef Item *(Item::* Item_transformer) (uchar *arg)

Type for transformers used by Item::transform and Item::compile.

Parameters

arg	Argument used by the transformer. Really a typeless pointer in spite of the uchar type (historical reasons). The transformer needs to cast this to the desired pointer type

Returns: The transformed item

◆ Ref_item_array

typedef Bounds_checked_array<Item *> Ref_item_array

Enumeration Type Documentation

◆ monotonicity_info

enum monotonicity_info

Enumerator
NON_MONOTONIC
MONOTONIC_INCREASING
MONOTONIC_INCREASING_NOT_NULL
MONOTONIC_STRICT_INCREASING
MONOTONIC_STRICT_INCREASING_NOT_NULL

Function Documentation

◆ agg_item_charsets()

bool agg_item_charsets	(	DTCollation &	c,
		const char *	name,
		Item **	items,
		uint	nitems,
		uint	flags,
		int	item_sep,
		bool	only_consts
	)

◆ agg_item_charsets_for_comparison()

bool agg_item_charsets_for_comparison	(	DTCollation &	c,
		const char *	name,
		Item **	items,
		uint	nitems,
		int	item_sep = `1`
	)

inline

◆ agg_item_charsets_for_string_result()

bool agg_item_charsets_for_string_result	(	DTCollation &	c,
		const char *	name,
		Item **	items,
		uint	nitems,
		int	item_sep = `1`
	)

inline

◆ agg_item_collations_for_comparison()

bool agg_item_collations_for_comparison	(	DTCollation &	c,
		const char *	name,
		Item **	items,
		uint	nitems,
		uint	flags
	)

◆ agg_item_set_converter()

bool agg_item_set_converter	(	DTCollation &	coll,
		const char *	fname,
		Item **	args,
		uint	nargs,
		uint	flags,
		int	item_sep,
		bool	only_consts
	)

◆ AllItemsAreEqual()

bool AllItemsAreEqual	(	const Item const	a,
		const Item const	b,
		int	num_items,
		bool	binary_cmp
	)

Returns true iff all items in the two arrays (which must be of the same size) are equal, as in a->eq(b), after unwrapping refs and Item_cache objects.

◆ char_to_byte_length_safe()

static uint32 char_to_byte_length_safe	(	uint32	char_length_arg,
		uint32	mbmaxlen_arg
	)

inlinestatic

◆ CompileItem()

template<class T , class U >

Item * CompileItem	(	Item *	item,
		T &&	analyzer,
		U &&	transformer
	)

inline

Same as WalkItem, but for Item::compile().

Use as e.g.:

Item *item = CompileItem(root_item, [](Item *item) { return true; }, // Analyzer. [](Item *item) { return item; }); // Transformer.

◆ convert_and_print()

void convert_and_print	(	const String *	from_str,
		String *	to_str,
		const CHARSET_INFO *	to_cs
	)

Helper method: Convert string to the given charset, then print.

Parameters

from_str	String to be converted.
to_str	Query string.
to_cs	Character set to which the string is to be converted.

◆ CountHiddenFields()

size_t CountHiddenFields ( const mem_root_deque< Item * > & fields )

inline

◆ CountVisibleFields()

size_t CountVisibleFields ( const mem_root_deque< Item * > & fields )

inline

◆ double_from_string_with_check()

double double_from_string_with_check	(	const CHARSET_INFO *	cs,
		const char *	cptr,
		const char *	end
	)

◆ FindEqualField()

Item_field * FindEqualField	(	Item_field *	item_field,
		table_map	reachable_tables,
		bool	replace,
		bool *	found
	)

◆ GetNthVisibleField()

Item * GetNthVisibleField	(	const mem_root_deque< Item * > &	fields,
		size_t	index
	)

inline

◆ is_null_on_empty_table()

bool is_null_on_empty_table	(	THD *	thd,
		Item_field *	i
	)

Check if the column reference that is currently being resolved, will be set to NULL if its qualifying query returns zero rows.

This is true for non-aggregated column references in the SELECT list, if the query block uses aggregation without grouping. For example:

SELECT COUNT(*), col FROM t WHERE some_condition

Here, if the table t is empty, or some_condition doesn't match any rows in t, the query returns one row where col is NULL, even if col is a not-nullable column.

Such column references are rejected if the ONLY_FULL_GROUP_BY SQL mode is enabled, in a later resolution phase.

◆ item_cmp_type()

Item_result item_cmp_type	(	Item_result	a,
		Item_result	b
	)

◆ item_init()

void item_init ( void )

Init all special items.

◆ ItemsAreEqual()

bool ItemsAreEqual	(	const Item *	a,
		const Item *	b,
		bool	binary_cmp
	)

Returns true iff the two items are equal, as in a->eq(b), after unwrapping refs and Item_cache objects.

◆ ItemToString()

std::string ItemToString ( const Item * item )

◆ longlong_from_string_with_check()

longlong longlong_from_string_with_check	(	const CHARSET_INFO *	cs,
		const char *	cptr,
		const char *	end,
		int	unsigned_target
	)

Converts a string to a longlong integer, with warnings.

Parameters

cs	charset of string
cptr	beginning of string
end	end of string
unsigned_target	If 0, caller will use result as a signed integer; if 1: an unsigned integer; if -1: caller doesn't tell. This influences warnings.

◆ new_Cached_item()

Cached_item * new_Cached_item	(	THD *	thd,
		Item *	item
	)

Create right type of Cached_item for an item.

◆ NO_FIELD_INDEX()

constexpr uint16 NO_FIELD_INDEX ( (uint16)(-1) )

inlineconstexpr

◆ numeric_context_result_type()

Item_result numeric_context_result_type	(	enum_field_types	data_type,
		Item_result	result_type,
		uint8	decimals
	)

inline

◆ resolve_const_item()

bool resolve_const_item	(	THD *	thd,
		Item **	ref,
		Item *	comp_item
	)

Substitute a const item with a simpler const item, if possible.

Parameters

	thd	Current session.
[in,out]	ref	Const item to be processed, contains simplest possible item on return.
	comp_item	Item that provides result type for generated const item

Returns: false if success, true if error

◆ SafeIncrement()

template<typename T >

void SafeIncrement ( T * num )

Increment *num if it is less than its maximal value.

◆ stored_field_cmp_to_item()

int stored_field_cmp_to_item	(	THD *	thd,
		Field *	field,
		Item *	item
	)

Compare the value stored in field with the expression from the query.

Parameters

thd	Current session.
field	Field which the Item is stored in after conversion
item	Original expression from query

Returns: Returns an integer greater than, equal to, or less than 0 if the value stored in the field is greater than, equal to, or less than the original Item. A 0 may also be returned if out of memory.

Note: We use this in the range optimizer/partition pruning, because in some cases we can't store the value in the field without some precision/character loss.

We similarly use it to verify that expressions like BIGINT_FIELD <cmp> <literal value> is done correctly (as int/decimal/float according to literal type).

◆ TransformItem()

template<class T >

Item * TransformItem	(	Item *	item,
		T &&	transformer
	)

Same as WalkItem, but for Item::transform().

Use as e.g.:

Item *item = TransformItem(root_item, [](Item *item) { return item; });

◆ WalkItem() [1/2]

template<class T >

bool WalkItem	(	const Item *	item,
		enum_walk	walk,
		T &&	functor
	)

inline

Overload for const 'item' and functor taking 'const Item*' argument.

◆ WalkItem() [2/2]

template<class T >

bool WalkItem	(	Item *	item,
		enum_walk	walk,
		T &&	functor
	)

inline

A helper class to give in a functor to Item::walk().

Use as e.g.:

bool result = WalkItem(root_item, enum_walk::POSTFIX, [](Item *item) { ... });

TODO: Make Item::walk() just take in a functor in the first place, instead of a pointer-to-member and an opaque argument.

Variable Documentation

◆ COND_FILTER_ALLPASS

constexpr float COND_FILTER_ALLPASS {1.0f}

constexpr

Default condition filtering (selectivity) values used by get_filtering_effect() and friends when better estimates (statistics) are not available for a predicate.

For predicates that are always satisfied. Must be 1.0 or the filter calculation logic will break down.

◆ COND_FILTER_BETWEEN

constexpr float COND_FILTER_BETWEEN {0.1111f}

constexpr

Filtering effect for between: col1 BETWEEN a AND b.

◆ COND_FILTER_EQUALITY

constexpr float COND_FILTER_EQUALITY {0.1f}

constexpr

Filtering effect for equalities: col1 = col2.

◆ COND_FILTER_INEQUALITY

constexpr float COND_FILTER_INEQUALITY {0.3333f}

constexpr

Filtering effect for inequalities: col1 > col2.

◆ COND_FILTER_STALE

constexpr float COND_FILTER_STALE {-1.0f}

constexpr

Value is out-of-date, will need recalculation.

This is used by post-greedy-search logic which changes the access method and thus makes obsolete the filtering value calculated by best_access_path(). For example, test_if_skip_sort_order().

◆ COND_FILTER_STALE_NO_CONST

constexpr float COND_FILTER_STALE_NO_CONST {-2.0f}

constexpr

A special subcase of the above:

if this is table/index/range scan, and
rows_fetched is how many rows we will examine, and
rows_fetched is less than the number of rows in the table (as determined by test_if_cheaper_ordering() and test_if_skip_sort_order()). Unlike the ordinary case where rows_fetched:
is set by calculate_scan_cost(), and
is how many rows pass the constant condition (so, less than we will examine), and
the actual rows_fetched to show in EXPLAIN is the number of rows in the table (== rows which we will examine), and
the constant condition's effect has to be moved to filter_effect for EXPLAIN.

◆ my_null_string

const String my_null_string

extern

◆ null_name_string

const Name_string null_name_string

extern

Classes

Macros

Typedefs

Enumerations

Functions

Variables

Macro Definition Documentation

◆ MY_COLL_ALLOW_COERCIBLE_CONV

◆ MY_COLL_ALLOW_CONV

◆ MY_COLL_ALLOW_NUMERIC_CONV

◆ MY_COLL_ALLOW_SUPERSET_CONV

◆ MY_COLL_CMP_CONV

◆ MY_COLL_DISALLOW_NONE

◆ NAME_STRING

Typedef Documentation

◆ Cond_traverser

◆ enum_monotonicity_info

◆ Item_analyzer

◆ Item_transformer

◆ Ref_item_array

Enumeration Type Documentation

◆ monotonicity_info

Function Documentation

◆ agg_item_charsets()

◆ agg_item_charsets_for_comparison()

◆ agg_item_charsets_for_string_result()

◆ agg_item_collations_for_comparison()

◆ agg_item_set_converter()

◆ AllItemsAreEqual()

◆ char_to_byte_length_safe()

◆ CompileItem()

◆ convert_and_print()

◆ CountHiddenFields()

◆ CountVisibleFields()

◆ double_from_string_with_check()

◆ FindEqualField()

◆ GetNthVisibleField()

◆ is_null_on_empty_table()

◆ item_cmp_type()

◆ item_init()

◆ ItemsAreEqual()

◆ ItemToString()

◆ longlong_from_string_with_check()

◆ new_Cached_item()

◆ NO_FIELD_INDEX()

◆ numeric_context_result_type()

◆ resolve_const_item()

◆ SafeIncrement()

◆ stored_field_cmp_to_item()

◆ TransformItem()

◆ WalkItem() [1/2]

◆ WalkItem() [2/2]

Variable Documentation

◆ COND_FILTER_ALLPASS

◆ COND_FILTER_BETWEEN

◆ COND_FILTER_EQUALITY

◆ COND_FILTER_INEQUALITY

◆ COND_FILTER_STALE

◆ COND_FILTER_STALE_NO_CONST

◆ my_null_string

◆ null_name_string