#include <item.h>

Inheritance diagram for Item_cache:

Public Member Functions
	Item_cache ()

	Item_cache (enum_field_types field_type_arg)

void	fix_after_pullout (Query_block parent_query_block, Query_block removed_query_block) override
	Fix after tables have been moved from one query_block level to the parent level, e.g by semijoin conversion. More...

virtual bool	allocate (uint)

virtual bool	setup (Item *item)

enum Type	type () const override

table_map	used_tables () const override

void	print (const THD thd, String str, enum_query_type query_type) const override
	This method is used for to: More...

bool	eq_def (const Field *field)

bool	eq (const Item *item, bool) const override

bool	has_value ()
	Check if saved item has a non-NULL value. More...

Field *	field ()
	If this item caches a field value, return pointer to underlying field. More...

virtual void	store (Item *item)
	Assigns to the cache the expression to be cached. More...

void	store_null ()
	Force an item to be null. More...

virtual bool	cache_value ()=0

bool	store_and_cache (Item *item)

void	cleanup () override
	Called for every Item after use (preparation and execution). More...

bool	basic_const_item () const override
	Returns true if this is a simple constant item like an integer, not a constant expression. More...

bool	walk (Item_processor processor, enum_walk walk, uchar *arg) override
	Traverses a tree of Items in prefix and/or postfix order. More...

virtual void	clear ()

bool	is_null () override
	The method allows to determine nullness of a complex expression without fully evaluating it, instead of calling val*() then checking null_value. More...

bool	is_non_const_over_literals (uchar *) override

bool	check_function_as_value_generator (uchar *args) override
	Check if this item is allowed for a virtual column or inside a default expression. More...

Item_result	result_type () const override

Item *	get_example () const

Item **	get_example_ptr ()

Public Member Functions inherited from Item_basic_constant
	Item_basic_constant ()

	Item_basic_constant (const POS &pos)

void	set_used_tables (table_map map)

void	set_str_value (String *str)

Public Member Functions inherited from Item
	Item (const Item &)=delete

void	operator= (Item &)=delete

	Item ()
	Item constructor for general use. More...

	Item (THD thd, const Item item)
	Constructor used by Item_field, Item_ref & aggregate functions. More...

	Item (const POS &)
	Parse-time context-independent constructor. More...

	~Item () override=default

virtual bool	itemize (Parse_context pc, Item *res) final
	The same as contextualize() but with additional parameter. More...

void	rename (char *new_name)
	rename item (used for views, cleanup() return original name). More...

void	init_make_field (Send_field *tmp_field, enum enum_field_types type)

virtual void	notify_removal ()
	Called when an item has been removed, can be used to notify external objects about the removal, e.g subquery predicates that are part of the sj_candidates container. More...

virtual void	make_field (Send_field *field)

virtual Field *	make_string_field (TABLE *table) const
	Create a field to hold a string value from an item. More...

virtual bool	fix_fields (THD , Item *)

void	quick_fix_field ()

virtual void	set_can_use_prefix_key ()

virtual bool	propagate_type (THD *thd, const Type_properties &type)
	Propagate data type specifications into parameters and user variables. More...

bool	propagate_type (THD *thd, enum_field_types def=MYSQL_TYPE_VARCHAR, bool pin=false, bool inherit=false)
	Wrapper for easier calling of propagate_type(const Type_properties &). More...

virtual void	mark_json_as_scalar ()
	For Items with data type JSON, mark that a string argument is treated as a scalar JSON value. More...

virtual std::optional< ContainedSubquery >	get_contained_subquery (const Query_block *outer_query_block)
	If this item represents a IN/ALL/ANY/comparison_operator subquery, return that (along with data on how it will be executed). More...

type_conversion_status	save_in_field_no_warnings (Field *field, bool no_conversions)
	Save the item into a field but do not emit any warnings. More...

type_conversion_status	save_in_field (Field *field, bool no_conversions)
	Save a temporal value in packed longlong format into a Field. More...

void	save_in_field_no_error_check (Field *field, bool no_conversions)
	A slightly faster value of save_in_field() that returns no error value (you will need to check thd->is_error() yourself), and does not support saving into hidden fields for functional indexes. More...

virtual void	save_org_in_field (Field *field)

virtual bool	send (Protocol protocol, String str)
	This is only called from items that is not of type item_field. More...

bool	evaluate (THD thd, String str)
	Evaluate scalar item, possibly using the supplied buffer. More...

virtual Item_result	numeric_context_result_type () const
	Result type when an item appear in a numeric context. More...

Item_result	temporal_with_date_as_number_result_type () const
	Similar to result_type() but makes DATE, DATETIME, TIMESTAMP pretend to be numbers rather than strings. More...

virtual void	set_data_type_inherited ()
	Set data type for item as inherited. More...

virtual void	pin_data_type ()
	Pin the data type for the item. More...

enum_field_types	data_type () const
	Retrieve the derived data type of the Item. More...

virtual enum_field_types	actual_data_type () const
	Retrieve actual data type for an item. More...

virtual enum_field_types	default_data_type () const
	Get the default data (output) type for the specific item. More...

void	set_data_type (enum_field_types data_type)
	Set the data type of the current Item. More...

void	set_data_type_null ()

void	set_data_type_bool ()

void	set_data_type_int (enum_field_types type, bool unsigned_prop, uint32 max_width)
	Set the data type of the Item to be a specific integer type. More...

void	set_data_type_longlong ()
	Set the data type of the Item to be longlong. More...

void	set_data_type_decimal (uint8 precision, uint8 scale)
	Set the data type of the Item to be decimal. More...

void	set_data_type_double ()
	Set the data type of the Item to be double precision floating point. More...

void	set_data_type_float ()
	Set the data type of the Item to be single precision floating point. More...

void	set_data_type_string (uint32 max_l)
	Set the Item to be variable length string. More...

void	set_data_type_string (ulonglong max_char_length_arg)
	Set the Item to be variable length string. More...

void	set_data_type_string (uint32 max_l, const CHARSET_INFO *cs)
	Set the Item to be variable length string. More...

void	set_data_type_string (uint32 max_l, const DTCollation &coll)
	Set the Item to be variable length string. More...

void	set_data_type_char (uint32 max_l)
	Set the Item to be fixed length string. More...

void	set_data_type_char (uint32 max_l, const CHARSET_INFO *cs)
	Set the Item to be fixed length string. More...

void	set_data_type_blob (enum_field_types type, uint32 max_l)
	Set the Item to be of BLOB type. More...

void	set_data_type_date ()
	Set all type properties for Item of DATE type. More...

void	set_data_type_time (uint8 fsp)
	Set all type properties for Item of TIME type. More...

void	set_data_type_datetime (uint8 fsp)
	Set all properties for Item of DATETIME type. More...

void	set_data_type_timestamp (uint8 fsp)
	Set all properties for Item of TIMESTAMP type. More...

void	set_data_type_geometry ()
	Set the data type of the Item to be GEOMETRY. More...

void	set_data_type_json ()
	Set the data type of the Item to be JSON. More...

void	set_data_type_year ()
	Set the data type of the Item to be YEAR. More...

void	set_data_type_bit (uint32 max_bits)
	Set the data type of the Item to be bit. More...

void	set_data_type_from_item (const Item *item)
	Set data type properties of the item from the properties of another item. More...

virtual TYPELIB *	get_typelib () const
	Get the typelib information for an item of type set or enum. More...

virtual Item_result	cast_to_int_type () const

bool	aggregate_type (const char name, Item *items, uint count)
	Aggregates data types from array of items into current item. More...

virtual enum_monotonicity_info	get_monotonicity_info () const

virtual longlong	val_int_endpoint (bool left_endp, bool *incl_endp)

virtual double	val_real ()=0

virtual longlong	val_int ()=0

virtual longlong	val_date_temporal ()
	Return date value of item in packed longlong format. More...

virtual longlong	val_time_temporal ()
	Return time value of item in packed longlong format. More...

longlong	val_temporal_by_field_type ()
	Return date or time value of item in packed longlong format, depending on item field type. More...

longlong	int_sort_key ()
	Produces a key suitable for filesort. More...

longlong	val_temporal_with_round (enum_field_types type, uint8 dec)
	Get date or time value in packed longlong format. More...

ulonglong	val_uint ()

virtual String *	val_str (String *str)=0

virtual String *	val_str_ascii (String *str)

virtual my_decimal *	val_decimal (my_decimal *decimal_buffer)=0

virtual bool	val_bool ()

virtual bool	val_json (Json_wrapper *result)
	Get a JSON value from an Item. More...

virtual float	get_filtering_effect (THD thd, table_map filter_for_table, table_map read_tables, const MY_BITMAP fields_to_ignore, double rows_in_table)
	Calculate the filter contribution that is relevant for table 'filter_for_table' for this item. More...

bool	error_json ()
	Get the value to return from val_json() in case of errors. More...

bool	get_date_from_non_temporal (MYSQL_TIME *ltime, my_time_flags_t fuzzydate)
	Convert a non-temporal type to date. More...

bool	get_time_from_non_temporal (MYSQL_TIME *ltime)
	Convert a non-temporal type to time. More...

my_decimal *	error_decimal (my_decimal *decimal_value)
	Get the value to return from val_decimal() in case of errors. More...

String *	error_str ()
	Get the value to return from val_str() in case of errors. More...

type_conversion_status	save_time_in_field (Field *field)

type_conversion_status	save_date_in_field (Field *field)

type_conversion_status	save_str_value_in_field (Field field, String result)

virtual Field *	get_tmp_table_field ()
	If this Item is being materialized into a temporary table, returns the field that is being materialized into. More...

virtual Field *	tmp_table_field (TABLE *)

virtual const char *	full_name () const

virtual table_map	not_null_tables () const
	Return table map of tables that can't be NULL tables (tables that are used in a context where if they would contain a NULL row generated by a LEFT or RIGHT join, the item would not be true). More...

bool	may_eval_const_item (const THD *thd) const

virtual Item *	clone_item () const

virtual cond_result	eq_cmp_result () const

uint	float_length (uint decimals_par) const

virtual uint	decimal_precision () const

int	decimal_int_part () const

virtual uint	time_precision ()
	TIME precision of the item: 0..6. More...

virtual uint	datetime_precision ()
	DATETIME precision of the item: 0..6. More...

bool	const_item () const
	Returns true if item is constant, regardless of query evaluation state. More...

bool	const_for_execution () const
	Returns true if item is constant during one query execution. More...

bool	may_evaluate_const (const THD *thd) const
	Return true if this is a const item that may be evaluated in the current phase of statement processing. More...

bool	is_non_deterministic () const

bool	is_outer_reference () const

void	print_item_w_name (const THD thd, String , enum_query_type query_type) const

void	print_for_order (const THD thd, String str, enum_query_type query_type, const char *used_alias) const
	Prints the item when it's part of ORDER BY and GROUP BY. More...

virtual void	update_used_tables ()
	Updates used tables, not null tables information and accumulates properties up the item tree, cf. More...

virtual bool	split_sum_func (THD , Ref_item_array, mem_root_deque< Item > *)

bool	split_sum_func2 (THD thd, Ref_item_array ref_item_array, mem_root_deque< Item > fields, Item *ref, bool skip_registered)

virtual bool	get_date (MYSQL_TIME *ltime, my_time_flags_t fuzzydate)=0

virtual bool	get_time (MYSQL_TIME *ltime)=0

virtual bool	get_timeval (my_timeval tm, int warnings)
	Get timestamp in "struct timeval" format. More...

bool	update_null_value ()
	Make sure the null_value member has a correct value. More...

virtual void	apply_is_true ()
	Apply the IS TRUE truth property, meaning that an UNKNOWN result and a FALSE result are treated the same. More...

virtual void	set_result_field (Field *)

virtual bool	is_result_field () const

virtual Field *	get_result_field () const

virtual bool	is_bool_func () const

virtual void	no_rows_in_result ()

virtual Item *	copy_or_same (THD *)

virtual Item *	copy_andor_structure (THD *)

virtual Item *	real_item ()

virtual const Item *	real_item () const

virtual Item *	get_tmp_table_item (THD *thd)
	If an Item is materialized in a temporary table, a different Item may have to be used in the part of the query that runs after the materialization. More...

virtual const CHARSET_INFO *	compare_collation () const

virtual const CHARSET_INFO *	charset_for_protocol ()

template<class T >
auto	walk_helper_thunk (uchar *arg)

template<class T >
auto	analyze_helper_thunk (uchar **arg)
	See CompileItem. More...

virtual Item *	transform (Item_transformer transformer, uchar *arg)
	Perform a generic transformation of the Item tree, by adding zero or more additional Item objects to it. More...

virtual Item *	compile (Item_analyzer analyzer, uchar *arg_p, Item_transformer transformer, uchar arg_t)
	Perform a generic "compilation" of the Item tree, ie transform the Item tree by adding zero or more Item objects to it. More...

virtual void	traverse_cond (Cond_traverser traverser, void *arg, traverse_order)

virtual bool	intro_version (uchar *)

bool	cleanup_processor (uchar *)
	cleanup() item if it is resolved ('fixed'). More...

virtual bool	collect_item_field_processor (uchar *)

virtual bool	collect_item_field_or_ref_processor (uchar *)

virtual bool	collect_item_field_or_view_ref_processor (uchar *)
	Collects fields and view references that have the qualifying table in the specified query block. More...

virtual bool	add_field_to_set_processor (uchar *)
	Item::walk function. More...

virtual bool	visitor_processor (uchar *arg)
	A processor to handle the select lex visitor framework. More...

virtual bool	add_field_to_cond_set_processor (uchar *)
	Item::walk function. More...

virtual bool	remove_column_from_bitmap (uchar *arg)
	Visitor interface for removing all column expressions (Item_field) in this expression tree from a bitmap. More...

virtual bool	find_item_in_field_list_processor (uchar *)

virtual bool	change_context_processor (uchar *)

virtual bool	find_item_processor (uchar *arg)

virtual bool	find_field_processor (uchar *)
	Is this an Item_field which references the given Field argument? More...

virtual bool	cast_incompatible_args (uchar *)
	Wrap incompatible arguments in CAST nodes to the expected data types. More...

virtual bool	mark_field_in_map (uchar *arg)
	Mark underlying field in read or write map of a table. More...

virtual bool	reset_wf_state (uchar *arg)
	Reset execution state for such window function types as determined by arg. More...

virtual bool	used_tables_for_level (uchar *arg)
	Return used table information for the specified query block (level). More...

virtual bool	check_column_privileges (uchar *thd)
	Check privileges. More...

virtual bool	inform_item_in_cond_of_tab (uchar *)

virtual void	bind_fields ()
	Bind objects from the current execution context to field objects in item trees. More...

virtual bool	clean_up_after_removal (uchar *arg)
	Clean up after removing the item from the item tree. More...

virtual bool	aggregate_check_distinct (uchar *)

virtual bool	aggregate_check_group (uchar *)

virtual bool	is_strong_side_column_not_in_fd (uchar *)

virtual bool	is_column_not_in_fd (uchar *)

virtual Bool3	local_column (const Query_block *) const

virtual bool	collect_scalar_subqueries (uchar *)

virtual bool	collect_grouped_aggregates (uchar *)

virtual bool	collect_subqueries (uchar *)

virtual bool	update_depended_from (uchar *)

virtual bool	has_aggregate_ref_in_group_by (uchar *)
	Check if an aggregate is referenced from within the GROUP BY clause of the query block in which it is aggregated. More...

bool	visit_all_analyzer (uchar **)

virtual bool	cache_const_expr_analyzer (uchar **cache_item)
	Check if an item is a constant one and can be cached. More...

Item *	cache_const_expr_transformer (uchar *item)
	Cache item if needed. More...

virtual bool	equality_substitution_analyzer (uchar **)

virtual Item *	equality_substitution_transformer (uchar *)

virtual bool	check_partition_func_processor (uchar *)
	Check if a partition function is allowed. More...

virtual bool	subst_argument_checker (uchar **arg)

virtual bool	explain_subquery_checker (uchar **)

virtual Item *	explain_subquery_propagator (uchar *)

virtual Item *	equal_fields_propagator (uchar *)

virtual bool	disable_constant_propagation (uchar *)

virtual Item *	replace_equal_field (uchar *)

virtual bool	replace_equal_field_checker (uchar **)

virtual bool	check_valid_arguments_processor (uchar *)

virtual bool	check_gcol_depend_default_processor (uchar *args)
	Check if a generated expression depends on DEFAULT function with specific column name as argument. More...

virtual bool	is_valid_for_pushdown (uchar *arg)
	Check if all the columns present in this expression are from the derived table. More...

virtual bool	check_column_in_window_functions (uchar *arg)
	Check if all the columns present in this expression are present in PARTITION clause of window functions of the derived table. More...

virtual bool	check_column_in_group_by (uchar *arg)
	Check if all the columns present in this expression are present in GROUP BY clause of the derived table. More...

virtual Item *	replace_with_derived_expr (uchar *arg)
	Assuming this expression is part of a condition that would be pushed to the WHERE clause of a materialized derived table, replace, in this expression, each derived table's column with a clone of the expression lying under it in the derived table's definition. More...

virtual Item *	replace_with_derived_expr_ref (uchar *arg)
	Assuming this expression is part of a condition that would be pushed to the HAVING clause of a materialized derived table, replace, in this expression, each derived table's column with a reference to the expression lying under it in the derived table's definition. More...

virtual Item *	replace_view_refs_with_clone (uchar *arg)
	Assuming this expression is part of a condition that would be pushed to a materialized derived table, replace, in this expression, each view reference with a clone of the expression in merged derived table's definition. More...

virtual Item *	this_item ()

virtual const Item *	this_item () const

virtual Item **	this_item_addr (THD , Item *addr_arg)

virtual uint	cols () const

virtual Item *	element_index (uint)

virtual Item **	addr (uint)

virtual bool	check_cols (uint c)

virtual bool	null_inside ()

virtual void	bring_value ()

Field *	tmp_table_field_from_field_type (TABLE *table, bool fixed_length) const
	Create a field based on field_type of argument. More...

virtual Item_field *	field_for_view_update ()

virtual Item *	truth_transformer (THD *thd, Bool_test test)
	Informs an item that it is wrapped in a truth test, in case it wants to transforms itself to implement this test by itself. More...

virtual Item *	update_value_transformer (uchar *)

virtual Item *	replace_scalar_subquery (uchar *)
	When walking the item tree seeing an Item_singlerow_subselect matching a target, replace it with a substitute field used when transforming scalar subqueries into derived tables. More...

virtual Item *	replace_item_field (uchar *)
	Transform processor used by Query_block::transform_grouped_to_derived to replace fields which used to be at the transformed query block with corresponding fields in the new derived table containing the grouping operation of the original transformed query block. More...

virtual Item *	replace_func_call (uchar *)

virtual Item *	replace_item_view_ref (uchar *)

virtual Item *	replace_aggregate (uchar *)

virtual Item *	replace_outer_ref (uchar *)

virtual bool	update_aggr_refs (uchar *)
	A walker processor overridden by Item_aggregate_ref, q.v. More...

virtual Item *	safe_charset_converter (THD thd, const CHARSET_INFO tocs)

void	delete_self ()
	Delete this item. More...

virtual bool	is_splocal () const

virtual Settable_routine_parameter *	get_settable_routine_parameter ()

bool	is_temporal_with_date () const

bool	is_temporal_with_date_and_time () const

bool	is_temporal_with_time () const

bool	is_temporal () const

bool	has_compatible_context (Item *item) const
	Check whether this and the given item has compatible comparison context. More...

virtual Field::geometry_type	get_geometry_type () const

String *	check_well_formed_result (String *str, bool send_error, bool truncate)
	Verifies that the input string is well-formed according to its character set. More...

bool	eq_by_collation (Item item, bool binary_cmp, const CHARSET_INFO cs)

CostOfItem	cost () const

uint32	max_char_length () const

uint32	max_char_length (const CHARSET_INFO *cs) const

void	fix_char_length (uint32 max_char_length_arg)

virtual bool	is_outer_field () const

bool	is_blob_field () const
	Check if an item either is a blob field, or will be represented as a BLOB field if a field is created based on this item. More...

uint	reference_count () const

void	increment_ref_count ()
	Increment reference count. More...

uint	decrement_ref_count ()
	Decrement reference count. More...

bool	has_subquery () const

bool	has_stored_program () const

bool	has_aggregation () const

void	set_aggregation ()
	Set the "has aggregation" property. More...

void	reset_aggregation ()
	Reset the "has aggregation" property. More...

bool	has_wf () const

void	set_wf ()
	Set the "has window function" property. More...

bool	has_grouping_set_dep () const

void	set_group_by_modifier ()
	Set the property: this item (tree) contains a reference to a GROUP BY modifier (such as ROLLUP) More...

bool	has_grouping_func () const

void	set_grouping_func ()
	Set the property: this item is a call to GROUPING. More...

virtual bool	created_by_in2exists () const
	Whether this Item was created by the IN->EXISTS subquery transformation. More...

void	mark_subqueries_optimized_away ()

virtual bool	gc_subst_analyzer (uchar **)
	Analyzer function for GC substitution. More...

virtual Item *	gc_subst_transformer (uchar *)
	Transformer function for GC substitution. More...

virtual bool	replace_field_processor (uchar *)
	A processor that replaces any Fields with a Create_field_wrapper. More...

bool	can_be_substituted_for_gc (bool array=false) const
	Check if this item is of a type that is eligible for GC substitution. More...

void	aggregate_float_properties (enum_field_types type, Item **items, uint nitems)
	Set max_length and decimals of function if function is floating point and result length/precision depends on argument ones. More...

void	aggregate_decimal_properties (Item **items, uint nitems)
	Set data type, precision and scale of item of type decimal from list of items. More...

uint32	aggregate_char_width (Item **items, uint nitems)
	Calculate the maximum number of characters required by any of the items. More...

void	aggregate_temporal_properties (enum_field_types type, Item **items, uint nitems)
	Set data type and fractional seconds precision for temporal functions. More...

bool	aggregate_string_properties (enum_field_types type, const char name, Item *items, uint nitems)
	Aggregate string properties (character set, collation and maximum length) for string function. More...

void	aggregate_bit_properties (Item **items, uint nitems)
	Set data type and properties of a BIT column. More...

virtual bool	repoint_const_outer_ref (uchar *arg)
	This function applies only to Item_field objects referred to by an Item_ref object that has been marked as a const_item. More...

virtual bool	strip_db_table_name_processor (uchar *)

virtual void	compute_cost (CostOfItem *root_cost) const
	Compute the cost of evaluating this Item. More...

bool	is_abandoned () const

bool	is_nullable () const

void	set_nullable (bool nullable)

virtual bool	supports_partial_update (const Field_json *field) const
	Check if this expression can be used for partial update of a given JSON column. More...

virtual bool	returns_array () const
	Whether the item returns array of its data type. More...

virtual void	allow_array_cast ()
	A helper function to ensure proper usage of CAST(. More...

Public Member Functions inherited from Parse_tree_node_tmpl< Context >
virtual	~Parse_tree_node_tmpl ()=default

bool	is_contextualized () const

virtual bool	contextualize (Context *pc) final

void	error (Context *pc, const POS &pos) const
	syntax_error() function replacement for deferred reporting of syntax errors More...

void	error (Context pc, const POS &pos, const char msg) const
	syntax_error() function replacement for deferred reporting of syntax errors More...

void	errorf (Context pc, const POS &pos, const char format,...) const
	syntax_error() function replacement for deferred reporting of syntax errors More...

Static Public Member Functions
static Item_cache *	get_cache (const Item *item)

static Item_cache *	get_cache (const Item *item, const Item_result type)
	Get a cache item of given type. More...

Static Public Member Functions inherited from Item
static void *	operator new (size_t size) noexcept

static void *	operator new (size_t size, MEM_ROOT *mem_root, const std::nothrow_t &arg=std::nothrow) noexcept

static void	operator delete (void *ptr, size_t size)

static void	operator delete (void , MEM_ROOT , const std::nothrow_t &) noexcept

static enum_field_types	result_to_type (Item_result result)

static Item_result	type_to_result (enum_field_types type)

static enum_field_types	type_for_variable (enum_field_types src_type)
	Provide data type for a user or system variable, based on the type of the item that is assigned to the variable. More...

static enum_field_types	string_field_type (uint32 max_bytes)
	Determine correct string field type, based on string length. More...

static const CHARSET_INFO *	default_charset ()

Static Public Member Functions inherited from Parse_tree_node_tmpl< Context >
static void *	operator new (size_t size, MEM_ROOT *mem_root, const std::nothrow_t &arg=std::nothrow) noexcept

static void	operator delete (void *ptr, size_t size)

static void	operator delete (void , MEM_ROOT , const std::nothrow_t &) noexcept

Protected Attributes
Item *	example {nullptr}

table_map	used_table_map {0}

Item_field *	cached_field {nullptr}
	Field that this object will get value from. More...

bool	value_cached {false}

Protected Attributes inherited from Item
String	str_value
	str_values's main purpose is to cache the value in save_in_field More...

uint8	m_accum_properties

Friends
bool	has_rollup_result (Item *item)
	Checks if an item has a ROLLUP NULL which needs to be written to temp table. More...

bool	replace_contents_of_rollup_wrappers_with_tmp_fields (THD thd, Query_block select, Item *item_arg)
	For each rollup wrapper below the given item, replace its argument with a temporary field, e.g. More...

Additional Inherited Members
Public Types inherited from Item
enum	Type { INVALID_ITEM , FIELD_ITEM , FUNC_ITEM , SUM_FUNC_ITEM , AGGR_FIELD_ITEM , STRING_ITEM , INT_ITEM , DECIMAL_ITEM , REAL_ITEM , NULL_ITEM , HEX_BIN_ITEM , DEFAULT_VALUE_ITEM , COND_ITEM , REF_ITEM , INSERT_VALUE_ITEM , SUBQUERY_ITEM , ROW_ITEM , CACHE_ITEM , TYPE_HOLDER_ITEM , PARAM_ITEM , ROUTINE_FIELD_ITEM , TRIGGER_FIELD_ITEM , XPATH_NODESET_ITEM , VALUES_COLUMN_ITEM }

enum	cond_result { COND_UNDEF , COND_OK , COND_TRUE , COND_FALSE }

enum	traverse_order { POSTFIX , PREFIX }

enum	enum_const_item_cache { CACHE_NONE = 0 , CACHE_JSON_VALUE , CACHE_JSON_ATOM }
	How to cache constant JSON data. More...

enum	Bool_test { BOOL_IS_TRUE = 0x00 , BOOL_IS_FALSE = 0x01 , BOOL_IS_UNKNOWN = 0x02 , BOOL_NOT_TRUE = 0x03 , BOOL_NOT_FALSE = 0x04 , BOOL_NOT_UNKNOWN = 0x05 , BOOL_IDENTITY = 0x06 , BOOL_NEGATED = 0x07 , BOOL_ALWAYS_TRUE = 0x08 , BOOL_ALWAYS_FALSE = 0x09 }
	< Modifier for result transformation More...

enum	item_marker { MARKER_NONE = 0 , MARKER_IMPLICIT_NE_ZERO = 1 , MARKER_CONST_PROPAG = 2 , MARKER_BIT = 4 , MARKER_FUNC_DEP_NOT_NULL = 5 , MARKER_DISTINCT_GROUP = 6 , MARKER_COND_DERIVED_TABLE = 7 , MARKER_TRAVERSAL = 8 , MARKER_ICP_COND_USES_INDEX_ONLY = 10 }
	< Values for member 'marker' More...

Public Types inherited from Parse_tree_node_tmpl< Context >
typedef Context	context_t

Public Attributes inherited from Item
Item *	next_free
	Intrusive list pointer for free list. More...

DTCollation	collation
	Character set and collation properties assigned for this Item. More...

Item_name_string	item_name
	Name from query. More...

Item_name_string	orig_name
	Original item name (if it was renamed) More...

uint32	max_length
	Maximum length of result of evaluating this item, in number of bytes. More...

item_marker	marker
	This member has several successive meanings, depending on the phase we're in (. More...

Item_result	cmp_context
	Comparison context. More...

bool	fixed
	True if item has been resolved. More...

uint8	decimals
	Number of decimals in result when evaluating this item. More...

bool	null_value
	True if item is null. More...

bool	unsigned_flag

bool	m_is_window_function
	True if item represents window func. More...

bool	hidden {false}
	If the item is in a SELECT list (Query_block::fields) and hidden is true, the item wasn't actually in the list as given by the user (it was added by the optimizer, to e.g. More...

bool	m_in_check_constraint_exec_ctx {false}
	True if item is a top most element in the expression being evaluated for a check constraint. More...

Public Attributes inherited from Parse_tree_node_tmpl< Context >
POS	m_pos

Protected Member Functions inherited from Item
String *	make_empty_result ()
	Sets the result value of the function an empty string, using the current character set. More...

bool	skip_itemize (Item **res)
	Helper function to skip itemize() for grammar-allocated items. More...

virtual bool	do_itemize (Parse_context pc, Item *res)
	The core function that does the actual itemization. More...

virtual type_conversion_status	save_in_field_inner (Field *field, bool no_conversions)
	Helper function which does all of the work for save_in_field(Field*, bool), except some error checking common to all subclasses, which is performed by save_in_field() itself. More...

String *	val_string_from_real (String *str)

String *	val_string_from_int (String *str)

String *	val_string_from_decimal (String *str)

String *	val_string_from_date (String *str)

String *	val_string_from_datetime (String *str)

String *	val_string_from_time (String *str)

my_decimal *	val_decimal_from_real (my_decimal *decimal_value)

my_decimal *	val_decimal_from_int (my_decimal *decimal_value)

my_decimal *	val_decimal_from_string (my_decimal *decimal_value)

my_decimal *	val_decimal_from_date (my_decimal *decimal_value)

my_decimal *	val_decimal_from_time (my_decimal *decimal_value)

longlong	val_int_from_decimal ()

longlong	val_int_from_date ()

longlong	val_int_from_time ()

longlong	val_int_from_datetime ()

longlong	val_int_from_string ()

double	val_real_from_decimal ()

double	val_real_from_string ()

bool	error_bool ()
	Get the value to return from val_bool() in case of errors. More...

int	error_int ()
	Get the value to return from val_int() in case of errors. More...

double	error_real ()
	Get the value to return from val_real() in case of errors. More...

bool	error_date ()
	Get the value to return from get_date() in case of errors. More...

bool	error_time ()
	Get the value to return from get_time() in case of errors. More...

String *	null_return_str ()
	Gets the value to return from val_str() when returning a NULL value. More...

bool	get_date_from_string (MYSQL_TIME *ltime, my_time_flags_t flags)
	Convert val_str() to date in MYSQL_TIME. More...

bool	get_date_from_real (MYSQL_TIME *ltime, my_time_flags_t flags)
	Convert val_real() to date in MYSQL_TIME. More...

bool	get_date_from_decimal (MYSQL_TIME *ltime, my_time_flags_t flags)
	Convert val_decimal() to date in MYSQL_TIME. More...

bool	get_date_from_int (MYSQL_TIME *ltime, my_time_flags_t flags)
	Convert val_int() to date in MYSQL_TIME. More...

bool	get_date_from_time (MYSQL_TIME *ltime)
	Convert get_time() from time to date in MYSQL_TIME. More...

bool	get_date_from_numeric (MYSQL_TIME *ltime, my_time_flags_t fuzzydate)
	Convert a numeric type to date. More...

bool	get_time_from_string (MYSQL_TIME *ltime)
	Convert val_str() to time in MYSQL_TIME. More...

bool	get_time_from_real (MYSQL_TIME *ltime)
	Convert val_real() to time in MYSQL_TIME. More...

bool	get_time_from_decimal (MYSQL_TIME *ltime)
	Convert val_decimal() to time in MYSQL_TIME. More...

bool	get_time_from_int (MYSQL_TIME *ltime)
	Convert val_int() to time in MYSQL_TIME. More...

bool	get_time_from_date (MYSQL_TIME *ltime)
	Convert date to time. More...

bool	get_time_from_datetime (MYSQL_TIME *ltime)
	Convert datetime to time. More...

bool	get_time_from_numeric (MYSQL_TIME *ltime)
	Convert a numeric type to time. More...

virtual longlong	val_date_temporal_at_utc ()

virtual longlong	val_time_temporal_at_utc ()

void	set_accum_properties (const Item *item)
	Set accumulated properties for an Item. More...

void	add_accum_properties (const Item *item)
	Add more accumulated properties to an Item. More...

void	set_subquery ()
	Set the "has subquery" property. More...

void	set_stored_program ()
	Set the "has stored program" property. More...

Protected Member Functions inherited from Parse_tree_node_tmpl< Context >
	Parse_tree_node_tmpl ()=delete

	Parse_tree_node_tmpl (const POS &pos)

	Parse_tree_node_tmpl (const POS &start_pos, const POS &end_pos)

bool	begin_parse_tree (Show_parse_tree *tree)

bool	end_parse_tree (Show_parse_tree *tree)

virtual bool	do_contextualize (Context *pc)
	Do all context-sensitive things and mark the node as contextualized. More...

virtual void	add_json_info (Json_object *json_obj)
	Add all the node-specific json fields. More...

Static Protected Member Functions inherited from Item
static bool	bit_func_returns_binary (const Item a, const Item b)

static bool	mark_field_in_map (Mark_field mark_field, Field field)
	Helper function for mark_field_in_map(uchar *arg). More...

Static Protected Attributes inherited from Item
static constexpr uint8	PROP_SUBQUERY = 0x01
	Set of properties that are calculated by accumulation from underlying items. More...

static constexpr uint8	PROP_STORED_PROGRAM = 0x02

static constexpr uint8	PROP_AGGREGATION = 0x04

static constexpr uint8	PROP_WINDOW_FUNCTION = 0x08

static constexpr uint8	PROP_HAS_GROUPING_SET_DEP = 0x10
	Set if the item or one or more of the underlying items contains a GROUP BY modifier (such as ROLLUP). More...

static constexpr uint8	PROP_GROUPING_FUNC = 0x20
	Set if the item or one or more of the underlying items is a GROUPING function. More...

Constructor & Destructor Documentation

◆ Item_cache() [1/2]

Item_cache::Item_cache ( )

inline

◆ Item_cache() [2/2]

Item_cache::Item_cache ( enum_field_types field_type_arg )

inline

Member Function Documentation

◆ allocate()

virtual bool Item_cache::allocate ( uint )

inlinevirtual

Reimplemented in Item_cache_row.

◆ basic_const_item()

bool Item_cache::basic_const_item ( ) const

inlineoverridevirtual

Returns true if this is a simple constant item like an integer, not a constant expression.

Used in the optimizer to propagate basic constants. It is assumed that val_xxx() does not modify the item's state for such items. It is also assumed that val_str() can be called with nullptr as argument as val_str() will return an internally cached const string.

Reimplemented from Item_basic_constant.

◆ cache_value()

virtual bool Item_cache::cache_value ( )

pure virtual

Implemented in Item_cache_int, Item_cache_real, Item_cache_decimal, Item_cache_str, Item_cache_row, Item_cache_datetime, and Item_cache_json.

◆ check_function_as_value_generator()

bool Item_cache::check_function_as_value_generator ( uchar * args )

inlineoverridevirtual

Check if this item is allowed for a virtual column or inside a default expression.

Should be overridden in child classes.

Parameters

[in,out] args Due to the limitation of Item::walk() it is declared as a pointer to uchar, underneath there's a actually a structure of type Check_function_as_value_generator_parameters. It is used mainly in Item_field.

Returns: true if function is not accepted

Reimplemented from Item_basic_constant.

◆ cleanup()

void Item_cache::cleanup ( )

overridevirtual

Called for every Item after use (preparation and execution).

Release all allocated resources, such as dynamic memory. Prepare for new execution by clearing cached values. Do not remove values allocated during preparation, destructor handles this.

Reimplemented from Item_basic_constant.

Reimplemented in Item_cache_row.

◆ clear()

virtual void Item_cache::clear ( )

inlinevirtual

Reimplemented in Item_cache_datetime.

◆ eq()

bool Item_cache::eq	(	const Item *	item,
		bool	binary_cmp
	)		const

inlineoverridevirtual

This function is called when:

Comparing items in the WHERE clause (when doing where optimization)
When trying to find an ORDER BY/GROUP BY item in the SELECT part
When matching fields in multiple equality objects (Item_equal)

Reimplemented from Item.

◆ eq_def()

bool Item_cache::eq_def ( const Field * field )

inline

◆ field()

Field * Item_cache::field ( )

inline

If this item caches a field value, return pointer to underlying field.

Returns: Pointer to field, or NULL if this is not a cache for a field value.

◆ fix_after_pullout()

void Item_cache::fix_after_pullout	(	Query_block *	parent_query_block,
		Query_block *	removed_query_block
	)

inlineoverridevirtual

Fix after tables have been moved from one query_block level to the parent level, e.g by semijoin conversion.

Basically re-calculate all attributes dependent on the tables.

Parameters

parent_query_block	query_block that tables are moved to.
removed_query_block	query_block that tables are moved away from, child of parent_query_block.

Reimplemented from Item.

◆ get_cache() [1/2]

Item_cache * Item_cache::get_cache ( const Item * item )

static

◆ get_cache() [2/2]

Item_cache * Item_cache::get_cache	(	const Item *	item,
		const Item_result	type
	)

static

Get a cache item of given type.

Parameters

item	value to be cached
type	required type of cache

Returns: cache item

◆ get_example()

Item * Item_cache::get_example ( ) const

inline

◆ get_example_ptr()

Item ** Item_cache::get_example_ptr ( )

inline

◆ has_value()

bool Item_cache::has_value ( )

Check if saved item has a non-NULL value.

Will cache value of saved item if not already done.

Returns: true if cached value is non-NULL.

◆ is_non_const_over_literals()

bool Item_cache::is_non_const_over_literals ( uchar * )

inlineoverridevirtual

Reimplemented from Item.

◆ is_null()

bool Item_cache::is_null ( )

inlineoverridevirtual

The method allows to determine nullness of a complex expression without fully evaluating it, instead of calling val*() then checking null_value.

Used in Item_func_isnull/Item_func_isnotnull and Item_sum_count/Item_sum_count_distinct. Any item which can be NULL must implement this method.

Return values

false	if the expression is not NULL.
true	if the expression is NULL, or evaluation caused an error. The null_value member is set according to the return value.

Reimplemented from Item.

◆ print()

void Item_cache::print	(	const THD *	,
		String *	str,
		enum_query_type
	)		const

overridevirtual

This method is used for to:

to generate a view definition query (SELECT-statement);
to generate a SQL-query for EXPLAIN EXTENDED;
to generate a SQL-query to be shown in INFORMATION_SCHEMA;
to generate a SQL-query that looks like a prepared statement for query_rewrite
debug.

For more information about view definition query, INFORMATION_SCHEMA query and why they should be generated from the Item-tree,

See also: mysql_register_view().

Reimplemented from Item.

◆ result_type()

Item_result Item_cache::result_type ( ) const

inlineoverridevirtual

Reimplemented from Item.

Reimplemented in Item_cache_int, Item_cache_real, Item_cache_decimal, Item_cache_str, Item_cache_row, Item_cache_datetime, and Item_cache_json.

◆ setup()

virtual bool Item_cache::setup ( Item * item )

inlinevirtual

Reimplemented in Item_cache_row.

◆ store()

void Item_cache::store ( Item * item )

virtual

Assigns to the cache the expression to be cached.

Does not evaluate it.

Parameters

item	the expression to be cached

Reimplemented in Item_cache_row, and Item_cache_datetime.

◆ store_and_cache()

bool Item_cache::store_and_cache ( Item * item )

inline

◆ store_null()

void Item_cache::store_null ( )

inline

Force an item to be null.

Used for empty subqueries to avoid attempts to evaluate expressions which could have uninitialized columns due to bypassing the subquery exec.

◆ type()

enum Type Item_cache::type ( ) const

inlineoverridevirtual

Implements Item.

◆ used_tables()

table_map Item_cache::used_tables ( ) const

inlineoverridevirtual

Reimplemented from Item_basic_constant.

◆ walk()

bool Item_cache::walk	(	Item_processor	processor,
		enum_walk	walk,
		uchar *	arg
	)

overridevirtual

Traverses a tree of Items in prefix and/or postfix order.

Optionally walks into subqueries.

Parameters

processor	processor function to be invoked per item returns true to abort traversal, false to continue
walk	controls how to traverse the item tree enum_walk::PREFIX: call processor before invoking children enum_walk::POSTFIX: call processor after invoking children enum_walk::SUBQUERY go down into subqueries walk values are bit-coded and may be combined. Omitting both enum_walk::PREFIX and enum_walk::POSTFIX is undefined behaviour.
arg	Optional pointer to a walk-specific object

Return values

false	walk succeeded
true	walk aborted by agreement, an error may have been reported

Reimplemented from Item.

Friends And Related Function Documentation

◆ has_rollup_result

bool has_rollup_result ( Item * item )

friend

Checks if an item has a ROLLUP NULL which needs to be written to temp table.

Parameters

item	Item for which we need to detect if ROLLUP NULL has to be written.

Returns: false if ROLLUP NULL need not be written for this item. true if it has to be written.

◆ replace_contents_of_rollup_wrappers_with_tmp_fields

bool replace_contents_of_rollup_wrappers_with_tmp_fields	(	THD *	thd,
		Query_block *	select,
		Item *	item_arg
	)

friend

For each rollup wrapper below the given item, replace its argument with a temporary field, e.g.

1 + rollup_group_item(a) -> 1 + rollup_group_item(<temporary>.a).

Which temporary field to use is found by looking at the Query_block's group items, and looking up their (previously set) result fields.

Member Data Documentation

◆ cached_field

Item_field* Item_cache::cached_field {nullptr}

protected

Field that this object will get value from.

This is used by index-based subquery engines to detect and remove the equality injected by IN->EXISTS transformation.

◆ example

Item* Item_cache::example {nullptr}

protected

◆ used_table_map

table_map Item_cache::used_table_map {0}

protected

◆ value_cached

bool Item_cache::value_cached {false}

protected

The documentation for this class was generated from the following files:

sql/item.h
sql/item.cc

Public Member Functions

Static Public Member Functions

Protected Attributes

Friends

Additional Inherited Members

Constructor & Destructor Documentation

◆ Item_cache() [1/2]

◆ Item_cache() [2/2]

Member Function Documentation

◆ allocate()

◆ basic_const_item()

◆ cache_value()

◆ check_function_as_value_generator()

◆ cleanup()

◆ clear()

◆ eq()

◆ eq_def()

◆ field()

◆ fix_after_pullout()

◆ get_cache() [1/2]

◆ get_cache() [2/2]

◆ get_example()

◆ get_example_ptr()

◆ has_value()

◆ is_non_const_over_literals()

◆ is_null()

◆ print()

◆ result_type()

◆ setup()

◆ store()

◆ store_and_cache()

◆ store_null()

◆ type()

◆ used_tables()

◆ walk()

Friends And Related Function Documentation

◆ has_rollup_result

◆ replace_contents_of_rollup_wrappers_with_tmp_fields

Member Data Documentation

◆ cached_field

◆ example

◆ used_table_map

◆ value_cached