Item_subselect Class Reference

Inheritance diagram for Item_subselect:

Collaboration diagram for Item_subselect:

Public Types
enum	trans_res { RES_OK, RES_REDUCE, RES_ERROR }
enum	subs_type {   UNKNOWN_SUBS, SINGLEROW_SUBS, EXISTS_SUBS, IN_SUBS,   ALL_SUBS, ANY_SUBS }

Public Member Functions
const subselect_engine *	get_engine_for_explain () const
	EXPLAIN needs read-only access to the engine.
virtual subs_type	substype ()
virtual void	init (st_select_lex *select_lex, select_result_interceptor *result)
virtual void	cleanup ()
virtual void	reset ()
virtual trans_res	select_transformer (JOIN *join)
bool	assigned () const
void	assigned (bool a)
enum Type	type () const
bool	is_null ()
bool	fix_fields (THD *thd, Item **ref)
void	fix_after_pullout (st_select_lex *parent_select, st_select_lex *removed_select)
virtual bool	exec ()
virtual void	fix_length_and_dec ()
table_map	used_tables () const
table_map	not_null_tables () const
bool	const_item () const
table_map	get_used_tables_cache ()
bool	get_const_item_cache ()
Item *	get_tmp_table_item (THD *thd)
void	update_used_tables ()
virtual void	print (String *str, enum_query_type query_type)
virtual bool	have_guarded_conds ()
bool	change_engine (subselect_engine *eng)
bool	is_evaluated () const
bool	is_uncacheable () const
virtual void	reset_value_registration ()
enum_parsing_place	place ()
bool	walk_join_condition (List< TABLE_LIST > *tables, Item_processor processor, bool walk_subquery, uchar *argument)
bool	walk_body (Item_processor processor, bool walk_subquery, uchar *arg)
bool	walk (Item_processor processor, bool walk_subquery, uchar *arg)
virtual bool	explain_subquery_checker (uchar **arg)
bool	inform_item_in_cond_of_tab (uchar *join_tab_index)
virtual bool	clean_up_after_removal (uchar *arg)
const char *	func_name () const
Public Member Functions inherited from Item_result_field
	Item_result_field (THD *thd, Item_result_field *item)
Field *	get_tmp_table_field ()
Field *	tmp_table_field (TABLE *t_arg)
void	set_result_field (Field *field)
bool	is_result_field ()
void	save_in_result_field (bool no_conversions)
Public Member Functions inherited from Item
	Item (THD *thd, Item *item)
void	rename (char *new_name)
void	init_make_field (Send_field *tmp_field, enum enum_field_types type)
virtual void	make_field (Send_field *field)
virtual Field *	make_string_field (TABLE *table)
void	quick_fix_field ()
type_conversion_status	save_in_field_no_warnings (Field *field, bool no_conversions)
virtual type_conversion_status	save_in_field (Field *field, bool no_conversions)
virtual void	save_org_in_field (Field *field)
virtual type_conversion_status	save_safe_in_field (Field *field)
virtual bool	send (Protocol *protocol, String *str)
virtual bool	eq (const Item *, bool binary_cmp) const
virtual Item_result	result_type () const
virtual enum Item_result	numeric_context_result_type () const
enum Item_result	temporal_with_date_as_number_result_type () const
virtual Item_result	cast_to_int_type () const
virtual enum_field_types	string_field_type () const
virtual enum_field_types	field_type () const
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 ()
virtual longlong	val_time_temporal ()
longlong	val_temporal_by_field_type ()
longlong	val_temporal_with_round (enum_field_types type, uint8 dec)
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 String *	val_nodeset (String *)
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 const char *	full_name () const
virtual double	val_result ()
virtual longlong	val_int_result ()
virtual longlong	val_time_temporal_result ()
virtual longlong	val_date_temporal_result ()
virtual String *	str_result (String *tmp)
virtual my_decimal *	val_decimal_result (my_decimal *val)
virtual bool	val_bool_result ()
virtual bool	is_null_result ()
virtual table_map	resolved_used_tables () const
virtual bool	basic_const_item () const
virtual Item *	clone_item ()
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 ()
virtual uint	datetime_precision ()
virtual bool	const_during_execution () const
void	print_item_w_name (String *, enum_query_type query_type)
void	print_for_order (String *str, enum_query_type query_type, bool used_alias)
virtual void	split_sum_func (THD *thd, Ref_ptr_array ref_pointer_array, List< Item > &fields)
void	split_sum_func2 (THD *thd, Ref_ptr_array ref_pointer_array, List< Item > &fields, Item **ref, bool skip_registered)
virtual bool	get_date (MYSQL_TIME *ltime, uint fuzzydate)=0
virtual bool	get_time (MYSQL_TIME *ltime)=0
virtual bool	get_timeval (struct timeval *tm, int *warnings)
virtual bool	get_date_result (MYSQL_TIME *ltime, uint fuzzydate)
virtual void	update_null_value ()
virtual void	top_level_item ()
virtual bool	is_bool_func ()
virtual void	no_rows_in_result ()
virtual Item *	copy_or_same (THD *thd)
virtual Item *	copy_andor_structure (THD *thd, bool real_items=false)
virtual Item *	real_item ()
virtual const CHARSET_INFO *	compare_collation ()
virtual const CHARSET_INFO *	charset_for_protocol (void) const
virtual Item *	transform (Item_transformer transformer, uchar *arg)
virtual Item *	compile (Item_analyzer analyzer, uchar **arg_p, Item_transformer transformer, uchar *arg_t)
virtual void	traverse_cond (Cond_traverser traverser, void *arg, traverse_order order)
virtual bool	intro_version (uchar *int_arg)
virtual bool	remove_dependence_processor (uchar *arg)
virtual bool	remove_fixed (uchar *arg)
virtual bool	cleanup_processor (uchar *arg)
virtual bool	collect_item_field_processor (uchar *arg)
virtual bool	add_field_to_set_processor (uchar *arg)
virtual bool	remove_column_from_bitmap (uchar *arg)
virtual bool	find_item_in_field_list_processor (uchar *arg)
virtual bool	change_context_processor (uchar *context)
virtual bool	reset_query_id_processor (uchar *query_id_arg)
virtual bool	find_item_processor (uchar *arg)
virtual bool	register_field_in_read_map (uchar *arg)
virtual bool	cache_const_expr_analyzer (uchar **arg)
virtual Item *	cache_const_expr_transformer (uchar *arg)
virtual bool	item_field_by_name_analyzer (uchar **arg)
virtual Item *	item_field_by_name_transformer (uchar *arg)
virtual bool	equality_substitution_analyzer (uchar **arg)
virtual Item *	equality_substitution_transformer (uchar *arg)
virtual bool	check_partition_func_processor (uchar *bool_arg)
virtual bool	subst_argument_checker (uchar **arg)
virtual Item *	explain_subquery_propagator (uchar *arg)
virtual Item *	equal_fields_propagator (uchar *arg)
virtual bool	set_no_const_sub (uchar *arg)
virtual Item *	replace_equal_field (uchar *arg)
virtual bool	check_valid_arguments_processor (uchar *bool_arg)
virtual bool	find_function_processor (uchar *arg)
virtual Item *	this_item ()
virtual const Item *	this_item () const
virtual Item **	this_item_addr (THD *thd, Item **addr_arg)
virtual uint	cols ()
virtual Item *	element_index (uint i)
virtual Item **	addr (uint i)
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)
virtual Item_field *	field_for_view_update ()
virtual Item *	neg_transformer (THD *thd)
virtual Item *	update_value_transformer (uchar *select_arg)
virtual Item *	safe_charset_converter (const CHARSET_INFO *tocs)
void	delete_self ()
virtual bool	is_splocal ()
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
virtual Field::geometry_type	get_geometry_type () const
String *	check_well_formed_result (String *str, bool send_error=0)
bool	eq_by_collation (Item *item, bool binary_cmp, const CHARSET_INFO *cs)
virtual bool	is_expensive ()
virtual bool	can_be_evaluated_now () const
uint32	max_char_length () const
void	fix_length_and_charset (uint32 max_char_length_arg, const CHARSET_INFO *cs)
void	fix_char_length (uint32 max_char_length_arg)
void	fix_char_length_ulonglong (ulonglong max_char_length_arg)
void	fix_length_and_charset_datetime (uint32 max_char_length_arg)
void	fix_length_and_dec_and_charset_datetime (uint32 max_char_length_arg, uint8 dec_arg)
virtual bool	is_outer_field () const
bool	is_blob_field () const
virtual bool	has_subquery () const
virtual bool	has_stored_program () const
virtual bool	created_by_in2exists () const
	Whether this Item was created by the IN->EXISTS subquery transformation.

Public Attributes
Item *	substitution
st_select_lex_unit *	unit
int	in_cond_of_tab
bool	engine_changed
bool	changed
Public Attributes inherited from Item_result_field
Field *	result_field
Public Attributes inherited from Item
uint	rsize
String	str_value
Item_name_string	item_name
Item_name_string	orig_name
Item *	next
uint32	max_length
int	marker
uint8	decimals
my_bool	maybe_null
my_bool	null_value
my_bool	unsigned_flag
my_bool	with_sum_func
my_bool	fixed
DTCollation	collation
Item_result	cmp_context

Protected Attributes
subselect_engine *	engine
subselect_engine *	old_engine
table_map	used_tables_cache
uint	max_columns
enum_parsing_place	parsing_place
bool	have_to_be_excluded
bool	const_item_cache

Friends
class	select_result_interceptor
class	Item_in_optimizer
bool	Item_field::fix_fields (THD *, Item **)
int	Item_field::fix_outer_field (THD *, Field **, Item **)
bool	Item_ref::fix_fields (THD *, Item **)
void	Item_ident::fix_after_pullout (st_select_lex *parent_select, st_select_lex *removed_selec)
void	mark_select_range_as_dependent (THD *, st_select_lex *, st_select_lex *, Field *, Item *, Item_ident *)

Additional Inherited Members
Static Public Member Functions inherited from Item
static void *	operator new (size_t size) throw ()
static void *	operator new (size_t size, MEM_ROOT *mem_root) throw ()
static void	operator delete (void *ptr, size_t size)
static void	operator delete (void *ptr, MEM_ROOT *mem_root)
static const CHARSET_INFO *	default_charset ()
Protected Member Functions inherited from Item
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 ()
double	val_real_from_decimal ()
bool	get_date_from_string (MYSQL_TIME *ltime, uint flags)
bool	get_date_from_real (MYSQL_TIME *ltime, uint flags)
bool	get_date_from_decimal (MYSQL_TIME *ltime, uint flags)
bool	get_date_from_int (MYSQL_TIME *ltime, uint flags)
bool	get_date_from_time (MYSQL_TIME *ltime)
bool	get_date_from_numeric (MYSQL_TIME *ltime, uint fuzzydate)
bool	get_date_from_non_temporal (MYSQL_TIME *ltime, uint fuzzydate)
bool	get_time_from_string (MYSQL_TIME *ltime)
bool	get_time_from_real (MYSQL_TIME *ltime)
bool	get_time_from_decimal (MYSQL_TIME *ltime)
bool	get_time_from_int (MYSQL_TIME *ltime)
bool	get_time_from_date (MYSQL_TIME *ltime)
bool	get_time_from_datetime (MYSQL_TIME *ltime)
bool	get_time_from_numeric (MYSQL_TIME *ltime)
bool	get_time_from_non_temporal (MYSQL_TIME *ltime)

Detailed Description

Definition at line 41 of file item_subselect.h.

Member Function Documentation

bool Item_subselect::clean_up_after_removal ( uchar *  arg )

virtual

Clean up after removing the subquery from the item tree.

Call st_select_lex_unit::exclude_tree() to unlink it from its master and to unlink direct st_select_lex children from all_selects_list.

Don't unlink subqueries that are not descendants of the starting point (root) of the removal and cleanup.

Reimplemented from Item.

Definition at line 2486 of file item_subselect.cc.

bool Item_subselect::explain_subquery_checker ( uchar **  arg )

virtual

Mark a subquery unit with information provided

A subquery may belong to WHERE, HAVING, ORDER BY or GROUP BY item trees. This "processor" qualifies subqueries by outer clause type.

Note

For the WHERE clause of the JOIN query this function also associates a related table with the unit.

Parameters

arg	Explain_subquery_marker structure

Return values

false

Note

We always return "false" as far as we don't want to dive deeper because we explain inner subqueries in their joins contexts.

Reimplemented from Item.

Definition at line 537 of file item_subselect.cc.

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void Item_subselect::fix_after_pullout ( st_select_lex *  parent_select, st_select_lex *  removed_select  )

virtual

Fix used tables information for a subquery after query transformations. Common actions for all predicates involving subqueries. Most actions here involve re-resolving information for conditions and items belonging to the subquery. Notice that the usage information from underlying expressions is not propagated to the subquery predicate, as it belongs to inner layers of the query operator structure. However, when underlying expressions contain outer references into a select_lex on this level, the relevant information must be updated when these expressions are resolved.

Reimplemented from Item.

Reimplemented in Item_in_subselect.

Definition at line 666 of file item_subselect.cc.

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bool Item_subselect::inform_item_in_cond_of_tab ( uchar *  join_tab_index )

virtual

Tells an Item that it is in the condition of a JOIN_TAB

Parameters

'join_tab_index'

index of JOIN_TAB in JOIN's array

The Item records this fact and can deduce from it the estimated number of times that it will be evaluated.

Reimplemented from Item.

Definition at line 2469 of file item_subselect.cc.

void Item_subselect::print ( String *  str, enum_query_type  query_type  )

virtual

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;
• 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.

Reimplemented in Item_allany_subselect, Item_in_subselect, Item_exists_subselect, and Item_maxmin_subselect.

Definition at line 817 of file item_subselect.cc.

bool Item_subselect::walk_body	(	Item_processor	processor,
		bool	walk_subquery,
		uchar *	argument
	)

Workaround for bug in gcc 4.1. Item_in_subselect::walk()

Definition at line 469 of file item_subselect.cc.

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bool Item_subselect::walk_join_condition	(	List< TABLE_LIST > *	tables,
		Item_processor	processor,
		bool	walk_subquery,
		uchar *	argument
	)

Apply walk() processor to join conditions.

JOINs may be nested. Walk nested joins recursively to apply the processor.

Definition at line 443 of file item_subselect.cc.

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Member Data Documentation

int Item_subselect::in_cond_of_tab

If !=INT_MIN: this Item is in the condition attached to the JOIN_TAB having this index in the parent JOIN.

Definition at line 73 of file item_subselect.h.

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

• sql/item_subselect.h
• sql/item_subselect.cc