This class represents a query block, aka a query specification, which is a query consisting of a SELECT keyword, followed by a table list, optionally followed by a WHERE clause, a GROUP BY, etc. More...

#include <sql_lex.h>

Inheritance diagram for Query_block:

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Public Types
enum	Resolve_place { RESOLVE_NONE , RESOLVE_JOIN_NEST , RESOLVE_CONDITION , RESOLVE_HAVING , RESOLVE_QUALIFY , RESOLVE_SELECT_LIST }
	Three fields used by semi-join transformations to know when semi-join is possible, and in which condition tree the subquery predicate is located. More...

Public Member Functions
	Query_block (MEM_ROOT mem_root, Item where, Item *having)
	Construct and initialize Query_block object. More...

void	debugPrint (int level, std::ostringstream &buf) const override
	Query_term methods overridden. More...

void	qbPrint (int level, std::ostringstream &buf) const
	Minion of debugPrint. More...

Query_term_type	term_type () const override
	Get the node tree type. More...

const char *	operator_string () const override
	Get the node type description. More...

Query_block *	query_block () const override
	The query_block which holds the ORDER BY and LIMIT information for this set operation. More...

void	label_children () override
	Set the correct value of `Query_term::m_sibling_idx` recursively for set operations. More...

void	destroy_tree () override
	Destroy the query term tree structure. More...

bool	open_result_tables (THD *, int) override
	Open tmp tables for the tree of set operation query results, by recursing. More...

bool	absorb_limit_of (Query_block *block)
	end of overridden methods from Query_term More...

Item *	where_cond () const

Item **	where_cond_ref ()

void	set_where_cond (Item *cond)

Item *	having_cond () const

Item **	having_cond_ref ()

void	set_having_cond (Item *cond)

Item *	qualify_cond () const

Item **	qualify_cond_ref ()

void	set_qualify_cond (Item *cond)

void	set_query_result (Query_result *result)

Query_result *	query_result () const

bool	change_query_result (THD thd, Query_result_interceptor new_result, Query_result_interceptor *old_result)
	Change the Query_result object of the query block. More...

void	set_base_options (ulonglong options_arg)
	Set base options for a query block (and active options too) More...

void	add_base_options (ulonglong options)
	Add base options to a query block, also update active options. More...

void	remove_base_options (ulonglong options)
	Remove base options from a query block. More...

void	make_active_options (ulonglong added_options, ulonglong removed_options)
	Make active options from base options, supplied options and environment: More...

void	add_active_options (ulonglong options)
	Adjust the active option set. More...

ulonglong	active_options () const

void	set_tables_readonly ()
	Set associated tables as read_only, ie. More...

table_map	all_tables_map () const

bool	remove_aggregates (THD thd, Query_block select)
	A minion of transform_grouped_to_derived. More...

Query_expression *	master_query_expression () const

Query_expression *	first_inner_query_expression () const

Query_block *	outer_query_block () const

Query_block *	next_query_block () const

Table_ref *	find_table_by_name (const Table_ident *ident)
	Finds a (possibly unresolved) table reference in the from clause by name. More...

Query_block *	next_select_in_list () const

void	mark_as_dependent (Query_block *last, bool aggregate)
	Mark all query blocks from this to 'last' as dependent. More...

bool	has_tables () const

bool	is_explicitly_grouped () const

bool	is_implicitly_grouped () const

bool	is_non_primitive_grouped () const

bool	is_grouped () const

bool	is_distinct () const

bool	is_ordered () const

bool	can_skip_distinct () const
	Based on the structure of the query at resolution time, it is possible to conclude that DISTINCT is useless and remove it. More...

bool	has_limit () const

bool	has_ft_funcs () const

bool	is_recursive () const

ORDER *	find_in_group_list (Item item, int rollup_level) const
	Finds a group expression matching the given item, or nullptr if none. More...

int	group_list_size () const

bool	has_windows () const

void	invalidate ()
	Invalidate by nulling out pointers to other Query_expressions and Query_blockes. More...

uint	get_in_sum_expr () const

bool	add_item_to_list (Item *item)

bool	add_ftfunc_to_list (Item_func_match *func)

Table_ref *	add_table_to_list (THD thd, Table_ident table, const char alias, ulong table_options, thr_lock_type flags=TL_UNLOCK, enum_mdl_type mdl_type=MDL_SHARED_READ, List< Index_hint > hints=nullptr, List< String > partition_names=nullptr, LEX_STRING option=nullptr, Parse_context *pc=nullptr)
	Add a table to list of used tables. More...

Item **	add_hidden_item (Item *item)
	Add item to the hidden part of select list. More...

void	remove_hidden_items ()
	Remove hidden items from select list. More...

Table_ref *	get_table_list () const

bool	init_nested_join (THD *thd)
	Initialize a new table list for a nested join. More...

Table_ref *	end_nested_join ()
	End a nested join table list. More...

Table_ref *	nest_last_join (THD *thd, size_t table_cnt=2)
	Nest last join operations. More...

bool	add_joined_table (Table_ref *table)
	Add a table to the current join list. More...

mem_root_deque< Item * > *	get_fields_list ()

auto	visible_fields ()
	Wrappers over fields / get_fields_list() that hide items where item->hidden, meant for range-based for loops. More...

auto	visible_fields () const

bool	check_view_privileges (THD *thd, Access_bitmask want_privilege_first, Access_bitmask want_privilege_next)
	Check privileges for views that are merged into query block. More...

bool	check_column_privileges (THD *thd)
	Check privileges for all columns referenced from query block. More...

bool	check_privileges_for_subqueries (THD *thd)
	Check privileges for column references in subqueries of a query block. More...

bool	setup_tables (THD thd, Table_ref tables, bool select_insert)
	Resolve and prepare information about tables for one query block. More...

bool	resolve_limits (THD *thd)
	Resolve OFFSET and LIMIT clauses. More...

bool	resolve_placeholder_tables (THD *thd, bool apply_semijoin)
	Resolve derived table, view, table function information for a query block. More...

void	propagate_unique_test_exclusion ()
	Propagate exclusion from table uniqueness test into subqueries. More...

void	merge_contexts (Query_block *inner)
	Merge name resolution context objects of a subquery into its parent. More...

bool	merge_derived (THD thd, Table_ref derived_table)
	Merge derived table into query block. More...

bool	flatten_subqueries (THD *thd)
	Convert semi-join subquery predicates into semi-join join nests. More...

void	update_semijoin_strategies (THD *thd)
	Update available semijoin strategies for semijoin nests. More...

Subquery_strategy	subquery_strategy (const THD *thd) const
	Returns which subquery execution strategies can be used for this query block. More...

bool	semijoin_enabled (const THD *thd) const
	Returns whether semi-join is enabled for this query block. More...

void	set_sj_candidates (Mem_root_array< Item_exists_subselect * > *sj_cand)

void	add_subquery_transform_candidate (Item_exists_subselect *predicate)

bool	has_sj_candidates () const

bool	has_subquery_transforms () const

bool	add_ftfunc_list (List< Item_func_match > *ftfuncs)
	Add full-text function elements from a list into this query block. More...

void	set_lock_for_table (const Lock_descriptor &descriptor, Table_ref *table)

void	set_lock_for_tables (thr_lock_type lock_type)
	Set lock for all tables in current query block. More...

void	init_order ()

void	cut_subtree ()

bool	test_limit ()

ha_rows	get_offset (const THD *thd) const
	Get offset for LIMIT. More...

ha_rows	get_limit (const THD *thd) const
	Get limit. More...

bool	set_context (Name_resolution_context *outer_context)
	Assign a default name resolution object for this query block. More...

bool	setup_base_ref_items (THD *thd)
	Setup the array containing references to base items. More...

void	print (const THD thd, String str, enum_query_type query_type)

void	print_query_block (const THD thd, String str, enum_query_type query_type)
	Print detail of the Query_block object. More...

void	print_update (const THD thd, String str, enum_query_type query_type)
	Print detail of the UPDATE statement. More...

void	print_delete (const THD thd, String str, enum_query_type query_type)
	Print detail of the DELETE statement. More...

void	print_insert (const THD thd, String str, enum_query_type query_type)
	Print detail of the INSERT statement. More...

void	print_hints (const THD thd, String str, enum_query_type query_type)
	Print detail of Hints. More...

bool	print_error (const THD thd, String str)
	Print error. More...

void	print_select_options (String *str)
	Print select options. More...

void	print_update_options (String *str)
	Print UPDATE options. More...

void	print_delete_options (String *str)
	Print DELETE options. More...

void	print_insert_options (String *str)
	Print INSERT options. More...

void	print_table_references (const THD thd, String str, Table_ref *table_list, enum_query_type query_type)
	Print list of tables. More...

void	print_item_list (const THD thd, String str, enum_query_type query_type)
	Print list of items in Query_block object. More...

void	print_update_list (const THD thd, String str, enum_query_type query_type, const mem_root_deque< Item * > &fields, const mem_root_deque< Item * > &values)
	Print assignments list. More...

void	print_insert_fields (const THD thd, String str, enum_query_type query_type)
	Print column list to be inserted into. More...

void	print_values (const THD thd, String str, enum_query_type query_type, const mem_root_deque< mem_root_deque< Item * > * > &values, const char *prefix)
	Print list of values, used in INSERT and for general VALUES clause. More...

void	print_from_clause (const THD thd, String str, enum_query_type query_type)
	Print list of tables in FROM clause. More...

void	print_where_cond (const THD thd, String str, enum_query_type query_type)
	Print list of conditions in WHERE clause. More...

void	print_group_by (const THD thd, String str, enum_query_type query_type)
	Print list of items in GROUP BY clause. More...

void	print_having (const THD thd, String str, enum_query_type query_type)
	Print list of items in HAVING clause. More...

void	print_qualify (const THD thd, String str, enum_query_type query_type) const
	Print list of items in QUALIFY clause. More...

void	print_windows (const THD thd, String str, enum_query_type query_type)
	Print details of Windowing functions. More...

void	print_order_by (const THD thd, String str, enum_query_type query_type) const
	Print list of items in ORDER BY clause. More...

void	print_limit (const THD thd, String str, enum_query_type query_type) const

bool	save_properties (THD *thd)
	Save properties of a prepared statement needed for repeated optimization. More...

bool	accept (Select_lex_visitor *visitor)
	Accept function for SELECT and DELETE. More...

void	cleanup (bool full) override
	Cleanup this subtree (this Query_block and all nested Query_blockes and Query_expressions). More...

void	cleanup_all_joins ()

void	destroy ()
	Destroy contained objects, in particular temporary tables which may have their own mem_roots. More...

bool	is_simple_query_block () const

bool	is_empty_query () const

void	set_empty_query ()
	Set query block as returning no data. More...

bool	agg_func_used () const

bool	json_agg_func_used () const

void	set_agg_func_used (bool val)

void	set_json_agg_func_used (bool val)

bool	right_joins () const

void	set_right_joins ()

enum_explain_type	type () const
	Lookup for Query_block type. More...

const char *	get_type_str ()
	Lookup for a type string. More...

bool	is_dependent () const

bool	is_cacheable () const

bool	source_table_is_one_row () const

void	include_down (LEX lex, Query_expression outer)
	Include query block inside a query expression. More...

void	include_neighbour (LEX lex, Query_block before)
	Include a query block next to another query block. More...

void	include_standalone (Query_expression *sel)
	Include query block inside a query expression, but do not link. More...

void	include_in_global (Query_block **plink)
	Include query block into global list. More...

void	include_chain_in_global (Query_block **start)
	Include chain of query blocks into global list. More...

void	renumber (LEX *lex)
	Renumber query blocks of contained query expressions. More...

bool	apply_local_transforms (THD *thd, bool prune)
	Does permanent transformations which are local to a query block (which do not merge it to another block). More...

bool	push_conditions_to_derived_tables (THD *thd)
	Pushes parts of the WHERE condition of this query block to materialized derived tables. More...

bool	get_optimizable_conditions (THD thd, Item new_where, Item *new_having)
	Returns disposable copies of WHERE/HAVING/ON conditions. More...

bool	validate_outermost_option (LEX lex, const char wrong_option) const
	Check if an option that can be used only for an outer-most query block is applicable to this query block. More...

bool	validate_base_options (LEX *lex, ulonglong options) const
	Validate base options for a query block. More...

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

bool	add_tables (THD thd, const Mem_root_array< Table_ident > *tables, ulong table_options, thr_lock_type lock_type, enum_mdl_type mdl_type)
	Add tables from an array to a list of used tables. More...

bool	resolve_rollup_wfs (THD *thd)
	Replace group by field references inside window functions with references in the presence of ROLLUP. More...

bool	setup_conds (THD *thd)
	Resolve WHERE condition and join conditions. More...

bool	prepare (THD thd, mem_root_deque< Item > *insert_field_list)
	Prepare query block for optimization. More...

bool	optimize (THD *thd, bool finalize_access_paths)
	Optimize a query block and all inner query expressions. More...

void	reset_nj_counters (mem_root_deque< Table_ref * > *join_list=nullptr)
	Set NESTED_JOIN::counter=0 in all nested joins in passed list. More...

Item *	single_visible_field () const

size_t	num_visible_fields () const

bool	field_list_is_empty () const

Item *	clone_expression (THD thd, Item item, Table_ref *derived_table)
	Creates a clone for the given expression by re-parsing the expression. More...

Item *	get_derived_expr (uint expr_index)
	Returns an expression from the select list of the query block using the field's index in a derived table. More...

MaterializePathParameters::Operand	setup_materialize_query_block (AccessPath child_path, TABLE dst_table) const
	Make materialization parameters for a query block given its input path and destination table,. More...

void	update_used_tables ()
	Update used tables information for all local expressions. More...

void	restore_cmd_properties ()
	Restore prepared statement properties for this query block and all underlying query expressions so they are ready for optimization. More...

bool	save_cmd_properties (THD *thd)
	Save prepared statement properties for a query block and underlying query expressions. More...

bool	is_row_count_valid_for_semi_join ()
	Check if the offset and limit are valid for a semijoin. More...

bool	allocate_grouping_sets (THD *thd)
	Initializes the grouping set if the query block includes GROUP BY modifiers. More...

bool	populate_grouping_sets (THD *thd)
	Populates the grouping sets if the query block includes non-primitive grouping. More...

int	get_number_of_grouping_sets () const

Public Member Functions inherited from Query_term
Query_term *	pushdown_limit_order_by (Query_term_set_op *parent=nullptr)
	Called after contextualization to simplify query, c.f. More...

bool	validate_structure (const Query_term *parent, int depth=0) const
	Return true if structure is too deep, i.e. More...

std::pair< bool, bool >	redundant_order_by (Query_block *block, int level)
	Determine if we have a redundant ORDER BY in block. More...

virtual	~Query_term ()=default
	Node destructor. More...

virtual size_t	child_count () const
	Get the number of children this node has. More...

Query_term_set_op *	parent () const
	Getter for m_parent, q.v. More...

void	set_sibling_idx (uint idx)
	Setter for `m_sibling_idx`, q.v. More...

uint	sibling_idx ()
	Getter for `m_sibling_idx`, q.v. More...

void	printPointers (std::ostringstream &buf) const
	Print the pointer of this node and its parent to buf. More...

void	set_setop_query_result (Query_result *rs)
	Setter for m_setop_query_result, q.v. More...

Query_result *	setop_query_result ()
	Getter for m_setop_query_result, q.v. More...

Query_result_union *	setop_query_result_union ()
	Getter for m_setop_query_result, q.v. Use only if we can down cast. More...

void	cleanup_query_result (bool full)
	Cleanup m_setop_query_result, q.v. More...

void	set_owning_operand ()
	Setter for m_owning_operand, q.v. More...

bool	owning_operand ()
	Getter for m_owning_operand, q.v. More...

void	set_result_table (Table_ref *tl)
	Setter for m_result_table, q.v. More...

Table_ref &	result_table ()
	Getter for m_result_table, q.v. More...

void	set_fields (mem_root_deque< Item * > *fields)

mem_root_deque< Item * > *	fields ()

Static Public Member Functions
static const char *	get_type_str (enum_explain_type type)

Static Public Member Functions inherited from Query_term
static void	indent (int level, std::ostringstream &buf)
	Print blank space indentation (unit: two) to buf according to level. More...

static void	print_order (const THD thd, String str, ORDER *ord, enum_query_type query_type)
	Print into str the order indicated in ord, using standard print_for_order Used by traditional explain. More...

Public Attributes
size_t	m_added_non_hidden_fields {0}

mem_root_deque< Item * >	fields
	All expressions needed after join and filtering, ie., select list, group by list, having clause, window clause, order by clause, including hidden fields. More...

List< Window >	m_windows
	All windows defined on the select, both named and inlined. More...

List< Item_func_match > *	ftfunc_list
	A pointer to ftfunc_list_alloc, list of full text search functions. More...

List< Item_func_match >	ftfunc_list_alloc {}

mem_root_deque< mem_root_deque< Item * > * > *	row_value_list {nullptr}
	The VALUES items of a table value constructor. More...

mem_root_deque< Table_ref * >	sj_nests
	List of semi-join nests generated for this query block. More...

SQL_I_List< Table_ref >	m_table_list {}
	List of tables in FROM clause - use Table_ref::next_local to traverse. More...

SQL_I_List< ORDER >	order_list {}
	ORDER BY clause. More...

Group_list_ptrs *	order_list_ptrs {nullptr}

SQL_I_List< ORDER >	group_list {}
	GROUP BY clause. More...

Group_list_ptrs *	group_list_ptrs {nullptr}

decltype(SQL_I_List< ORDER >::elements)	m_no_of_added_exprs {0}
	For an explicitly grouped, correlated, scalar subquery which is transformed to join with derived tables: the number of added non-column expressions. More...

Prealloced_array< Item_rollup_group_item *, 4 >	rollup_group_items

Prealloced_array< Item_rollup_sum_switcher *, 4 >	rollup_sums

Opt_hints_qb *	opt_hints_qb {nullptr}
	Query-block-level hints, for this query block. More...

char *	db {nullptr}

Table_ref *	recursive_reference {nullptr}
	If this query block is a recursive member of a recursive unit: the Table_ref, in this recursive member, referencing the query name. More...

LEX *	parent_lex {nullptr}
	Reference to LEX that this query block belongs to. More...

table_map	select_list_tables {0}
	The set of those tables whose fields are referenced in the select list of this select level. More...

table_map	outer_join {0}
	Bitmap of all inner tables from outer joins. More...

Name_resolution_context	context {}
	Context for name resolution for all column references except columns from joined tables. More...

Name_resolution_context *	first_context
	Pointer to first object in list of Name res context objects that have this query block as the base query block. More...

JOIN *	join {nullptr}
	After optimization it is pointer to corresponding JOIN. More...

mem_root_deque< Table_ref * >	m_table_nest
	Set of table references contained in outer-most join nest. More...

mem_root_deque< Table_ref * > *	m_current_table_nest
	Pointer to the set of table references in the currently active join. More...

Table_ref *	embedding {nullptr}
	table embedding the above list More...

Table_ref *	leaf_tables {nullptr}
	Points to first leaf table of query block. More...

Table_ref *	end_lateral_table {nullptr}
	Last table for LATERAL join, used by table functions. More...

Item *	select_limit {nullptr}
	LIMIT clause, NULL if no limit is given. More...

Item *	offset_limit {nullptr}
	LIMIT ... OFFSET clause, NULL if no offset is given. More...

Item_sum *	inner_sum_func_list {nullptr}
	Circular linked list of aggregate functions in nested query blocks. More...

Ref_item_array	base_ref_items
	Array of pointers to "base" items; one each for every selected expression and referenced item in the query block. More...

uint	select_number {0}
	Query block number (used for EXPLAIN) More...

Item::cond_result	cond_value {Item::COND_UNDEF}
	Saved values of the WHERE and HAVING clauses. More...

Item::cond_result	having_value {Item::COND_UNDEF}

enum_parsing_context	parsing_place {CTX_NONE}
	Parse context: indicates where the current expression is being parsed. More...

uint	in_sum_expr {0}
	Parse context: is inside a set function if this is positive. More...

uint	in_window_expr {0}
	Parse context: is inside a window function if this is positive. More...

Resolve_place	resolve_place
	Indicates part of query being resolved. More...

uint	select_n_where_fields {0}
	Number of fields used in select list or where clause of current select and all inner subselects. More...

uint	select_n_having_items {0}
	Number of items in the select list, HAVING clause, QUALIFY clause and ORDER BY clause. More...

uint	saved_cond_count {0}
	Number of arguments of and/or/xor in where/having/on. More...

uint	cond_count {0}
	Number of predicates after preparation. More...

uint	between_count {0}
	Number of between predicates in where/having/on. More...

uint	max_equal_elems {0}
	Maximal number of elements in multiple equalities. More...

uint	n_sum_items {0}
	Number of Item_sum-derived objects in this SELECT. More...

uint	n_child_sum_items {0}
	Number of Item_sum-derived objects in children and descendant SELECTs. More...

uint	n_scalar_subqueries {0}
	Keep track for allocation of base_ref_items: scalar subqueries may be replaced by a field during scalar_to_derived transformation. More...

uint	materialized_derived_table_count {0}
	Number of materialized derived tables and views in this query block. More...

uint	partitioned_table_count {0}
	Number of partitioned tables. More...

uint	with_wild {0}
	Number of wildcards used in the SELECT list. More...

uint	leaf_table_count {0}
	Number of leaf tables in this query block. More...

uint	derived_table_count {0}
	Number of derived tables and views in this query block. More...

uint	table_func_count {0}
	Number of table functions in this query block. More...

int	nest_level {0}
	Nesting level of query block, outer-most query block has level 0, its subqueries have level 1, etc. More...

olap_type	olap {UNSPECIFIED_OLAP_TYPE}
	Indicates whether this query block contains non-primitive grouping (such as ROLLUP). More...

enum_condition_context	condition_context {enum_condition_context::ANDS}

bool	is_table_value_constructor {false}
	If set, the query block is of the form VALUES row_list. More...

sub_select_type	linkage {UNSPECIFIED_TYPE}
	Describes context of this query block (e.g if it is a derived table). More...

uint8	uncacheable {0}
	result of this query can't be cached, bit field, can be : UNCACHEABLE_DEPENDENT UNCACHEABLE_RAND UNCACHEABLE_SIDEEFFECT More...

bool	first_execution {true}
	This variable is required to ensure proper work of subqueries and stored procedures. More...

bool	sj_pullout_done {false}
	True when semi-join pull-out processing is complete. More...

bool	m_was_implicitly_grouped {false}
	Used by nested scalar_to_derived transformations. More...

bool	skip_local_transforms {false}
	True: skip local transformations during prepare() call (used by INSERT) More...

bool	is_item_list_lookup {false}

bool	having_fix_field {false}
	true when having fix field called in processing of this query block More...

bool	group_fix_field {false}
	true when GROUP BY fix field called in processing of this query block More...

bool	with_sum_func {false}
	True if contains or aggregates set functions. More...

bool	subquery_in_having {false}
	HAVING clause contains subquery => we can't close tables before query processing end even if we use temporary table. More...

bool	m_use_select_limit {false}
	If true, use select_limit to limit number of rows selected. More...

bool	m_internal_limit {false}
	If true, limit object is added internally. More...

bool	exclude_from_table_unique_test {false}
	exclude this query block from unique_table() check More...

bool	no_table_names_allowed {false}
	used for global order by More...

uint	hidden_items_from_optimization {0}
	Hidden items added during optimization. More...

Table_ref *	resolve_nest
	Used when resolving outer join condition. More...

Private Member Functions
bool	save_order_properties (THD thd, SQL_I_List< ORDER > list, Group_list_ptrs **list_ptrs)
	Helper for save_properties() More...

bool	record_join_nest_info (mem_root_deque< Table_ref * > *tables)
	Record join nest info in the select block. More...

bool	simplify_joins (THD thd, mem_root_deque< Table_ref > join_list, bool top, bool in_sj, Item new_conds, uint changelog=nullptr)
	Simplify joins replacing outer joins by inner joins whenever it's possible. More...

void	clear_sj_expressions (NESTED_JOIN *nested_join)
	Remove semijoin condition for this query block. More...

bool	build_sj_cond (THD thd, NESTED_JOIN nested_join, Query_block subq_query_block, table_map outer_tables_map, Item sj_cond, bool simple_const)
	Build semijoin condition for th query block. More...

bool	decorrelate_condition (Semijoin_decorrelation &sj_decor, Table_ref *join_nest)
	Decorrelate the WHERE clause or a join condition of a subquery used in an IN or EXISTS predicate. More...

bool	convert_subquery_to_semijoin (THD thd, Item_exists_subselect subq_pred)
	Convert a subquery predicate of this query block into a Table_ref semi-join nest. More...

Table_ref *	synthesize_derived (THD thd, Query_expression unit, Item *join_cond, bool left_outer, bool use_inner_join)
	Create a new Table_ref object for this query block, for either: 1) a derived table which will replace the subquery, or 2) an extra derived table for handling grouping, if necessary, cf. More...

bool	transform_subquery_to_derived (THD thd, Table_ref out_tl, Query_expression subs_query_expression, Item_subselect subq, bool use_inner_join, bool reject_multiple_rows, Item join_condition, Item *lifted_where_cond)
	Converts a subquery to a derived table and inserts it into the FROM clause of the owning query block. More...

bool	transform_table_subquery_to_join_with_derived (THD thd, Item_exists_subselect subq_pred)
	Replace a table subquery ([NOT] {IN, EXISTS}) with a join to a derived table. More...

bool	setup_counts_over_partitions (THD thd, Table_ref derived, Lifted_expressions_map lifted_expressions, mem_root_deque< Item > &exprs_added_to_group_by, uint hidden_fields)
	Add all COUNT(0) to SELECT list of the derived table to be used for cardinality checking of the transformed subquery. More...

bool	add_inner_fields_to_select_list (THD thd, Lifted_expressions_map lifted_exprs, Item *selected_field_or_ref, const uint first_non_hidden)
	Minion of `decorrelate_derived_scalar_subquery_pre`. More...

bool	add_inner_func_calls_to_select_list (THD thd, Lifted_expressions_map lifted_exprs)

bool	add_inner_exprs_to_group_by (THD thd, List_iterator< Item > &inner_exprs, Item selected_item, bool selected_expr_added_to_group_by, mem_root_deque< Item > *exprs_added_to_group_by)
	Run through the inner expressions and add them to the block's GROUP BY if not already present. More...

bool	decorrelate_derived_scalar_subquery_pre (THD thd, Table_ref derived, Item lifted_where, Lifted_expressions_map lifted_where_expressions, bool added_card_check, size_t added_window_card_checks)
	We have a correlated scalar subquery, so we must do several things: More...

bool	decorrelate_derived_scalar_subquery_post (THD thd, Table_ref derived, Lifted_expressions_map *lifted_exprs, bool added_card_check, size_t added_window_card_checks)
	See explanation in companion method `decorrelate_derived_scalar_subquery_pre`. More...

void	replace_referenced_item (Item const old_item, Item const new_item)
	Replace item in select list and preserve its reference count. More...

void	remap_tables (THD *thd)
	Re-map table numbers for all tables in a query block. More...

void	mark_item_as_maybe_null_if_non_primitive_grouped (Item *item) const
	Marks occurrences of group by fields in a function's arguments as nullable, so that we do not optimize them away before we get to add the rollup wrappers. More...

Item *	resolve_rollup_item (THD thd, Item item)
	Resolve an item (and its tree) for rollup processing by replacing items matching grouped expressions with Item_rollup_group_items and updating properties (m_nullable, PROP_ROLLUP_FIELD). More...

bool	resolve_rollup (THD *thd)
	Resolve items in SELECT list and ORDER BY list for rollup processing. More...

bool	setup_wild (THD *thd)
	Expand all '*' in list of expressions with the matching column references. More...

bool	setup_order_final (THD *thd)
	Do final setup of ORDER BY clause, after the query block is fully resolved. More...

bool	setup_group (THD *thd)
	Resolve and set up the GROUP BY list. More...

void	fix_after_pullout (Query_block parent_query_block, Query_block removed_query_block)

bool	remove_redundant_subquery_clauses (THD *thd)
	For a table subquery predicate (IN/ANY/ALL/EXISTS/etc): since it does not support LIMIT the following clauses are redundant: More...

void	repoint_contexts_of_join_nests (mem_root_deque< Table_ref * > join_list)
	Go through a list of tables and join nests, recursively, and repoint its query_block pointer. More...

bool	empty_order_list (Query_block *sl)
	Empty the ORDER list. More...

bool	setup_join_cond (THD thd, mem_root_deque< Table_ref > *tables, bool in_update)
	Resolve join conditions for a join nest. More...

bool	find_common_table_expr (THD thd, Table_ident table_id, Table_ref tl, Parse_context pc, bool *found)
	Tries to match an identifier to the CTEs in scope; if matched, it modifies table_name, tl', and the matched with-list-element. More...

bool	transform_scalar_subqueries_to_join_with_derived (THD *thd)
	Transform eligible scalar subqueries in the SELECT list, WHERE condition, HAVING condition or JOIN conditions of a query block[*] to an equivalent derived table of a LEFT OUTER join, e.g. More...

bool	supported_correlated_scalar_subquery (THD thd, Item::Css_info subquery, Item **lifted_where)
	Called when the scalar subquery is correlated. More...

bool	replace_item_in_expression (Item *expr, bool was_hidden, Item::Item_replacement info, Item_transformer transformer)
	Minion of `transform_grouped_to_derived`. More...

bool	transform_grouped_to_derived (THD thd, bool break_off)
	Minion of `transform_scalar_subqueries_to_join_with_derived`. More...

bool	replace_subquery_in_expr (THD thd, Item::Css_info subquery, Table_ref tr, Item *expr)
	A minion of transform_scalar_subqueries_to_join_with_derived. More...

bool	nest_derived (THD thd, Item join_cond, mem_root_deque< Table_ref * > join_list, Table_ref new_derived_table)
	Push the generated derived table to the correct location inside a join nest. More...

bool	resolve_table_value_constructor_values (THD *thd)
	Resolve the rows of a table value constructor and aggregate the type of each column across rows. More...

void	delete_unused_merged_columns (mem_root_deque< Table_ref * > *tables)
	Delete unused columns from merged tables. More...

bool	prepare_values (THD *thd)
	Prepare a table value constructor query block for optimization. More...

bool	check_only_full_group_by (THD *thd)
	Runs checks mandated by ONLY_FULL_GROUP_BY. More...

bool	lift_fulltext_from_having_to_select_list (THD *thd)
	Copies all non-aggregated calls to the full-text search MATCH function from the HAVING clause to the SELECT list (as hidden items), so that we can materialize their result and not only their input. More...

Private Attributes
Mem_root_array< Item_exists_subselect * > *	sj_candidates {nullptr}
	Pointer to collection of subqueries candidate for semi/antijoin conversion. More...

int	hidden_order_field_count {0}
	How many expressions are part of the order by but not select list. More...

Query_block *	next {nullptr}
	Intrusive linked list of all query blocks within the same query expression. More...

Query_expression *	master {nullptr}
	The query expression containing this query block. More...

Query_expression *	slave {nullptr}
	The first query expression contained within this query block. More...

Query_block *	link_next {nullptr}
	Intrusive double-linked global list of query blocks. More...

Query_block **	link_prev {nullptr}

Query_result *	m_query_result {nullptr}
	Result of this query block. More...

ulonglong	m_base_options {0}
	Options assigned from parsing and throughout resolving, should not be modified after resolving is done. More...

ulonglong	m_active_options {0}
	Active options. More...

int	m_num_grouping_sets {0}
	If the query block includes non-primitive grouping, then these modifiers are represented as grouping sets. More...

Item *	m_where_cond
	Condition to be evaluated after all tables in a query block are joined. More...

Item *	m_having_cond
	Condition to be evaluated on grouped rows after grouping. More...

Item *	m_qualify_cond {nullptr}
	Condition to be evaluated after window functions. More...

int	hidden_group_field_count
	Number of GROUP BY expressions added to all_fields. More...

Ref_item_array	m_saved_base_items
	A backup of the items in base_ref_items at the end of preparation, so that base_ref_items can be restored between executions of prepared statements. More...

bool	has_sj_nests {false}
	True if query block has semi-join nests merged into it. More...

bool	has_aj_nests {false}

bool	m_right_joins {false}
	True if query block has right joins. More...

bool	allow_merge_derived {true}
	Allow merge of immediate unnamed derived tables. More...

bool	m_agg_func_used {false}

bool	m_json_agg_func_used {false}

bool	m_empty_query {false}
	True if query block does not generate any rows before aggregation, determined during preparation (not optimization). More...

Static Private Attributes
static const char *	type_str [static_cast< int >(enum_explain_type::EXPLAIN_total)]

Friends
class	Query_expression

class	Condition_context

Additional Inherited Members
Protected Attributes inherited from Query_term
Query_term_set_op *	m_parent {nullptr}
	Back pointer to the node whose child we are, or nullptr (root term). More...

uint	m_sibling_idx {0}
	If parent is non-null, this holds the index of the current sibling. More...

Query_result *	m_setop_query_result {nullptr}
	The query result for this term. More...

bool	m_owning_operand {false}
	The operand of a n-ary set operation (that owns the common query result) has this set to true. More...

Table_ref *	m_result_table {nullptr}
	Result temporary table for the set operation, if applicable. More...

mem_root_deque< Item * > *	m_fields {nullptr}
	Used only when streaming, i.e. More...

Detailed Description

This class represents a query block, aka a query specification, which is a query consisting of a SELECT keyword, followed by a table list, optionally followed by a WHERE clause, a GROUP BY, etc.

Member Enumeration Documentation

◆ Resolve_place

enum Query_block::Resolve_place

Three fields used by semi-join transformations to know when semi-join is possible, and in which condition tree the subquery predicate is located.

Enumerator
RESOLVE_NONE
RESOLVE_JOIN_NEST
RESOLVE_CONDITION
RESOLVE_HAVING
RESOLVE_QUALIFY
RESOLVE_SELECT_LIST

Constructor & Destructor Documentation

◆ Query_block()

Query_block::Query_block	(	MEM_ROOT *	mem_root,
		Item *	where,
		Item *	having
	)

Construct and initialize Query_block object.

@note the group_by and order_by lists below will probably be added to the
      constructor when the parser is converted into a true bottom-up design.

SQL_I_LIST<ORDER> *group_by, SQL_I_LIST<ORDER> order_by

Member Function Documentation

◆ absorb_limit_of()

bool Query_block::absorb_limit_of ( Query_block * block )

end of overridden methods from Query_term

◆ accept()

bool Query_block::accept ( Select_lex_visitor * visitor )

Accept function for SELECT and DELETE.

Parameters

visitor Select_lex_visitor Object

◆ active_options()

ulonglong Query_block::active_options ( ) const

inline

Returns: the active query options

◆ add_active_options()

void Query_block::add_active_options ( ulonglong options )

inline

Adjust the active option set.

◆ add_base_options()

void Query_block::add_base_options ( ulonglong options )

inline

Add base options to a query block, also update active options.

◆ add_ftfunc_to_list()

bool Query_block::add_ftfunc_to_list ( Item_func_match * func )

◆ add_item_to_list()

bool Query_block::add_item_to_list ( Item * item )

◆ add_subquery_transform_candidate()

void Query_block::add_subquery_transform_candidate ( Item_exists_subselect * predicate )

inline

◆ add_tables()

bool Query_block::add_tables	(	THD *	thd,
		const Mem_root_array< Table_ident * > *	tables,
		ulong	table_options,
		thr_lock_type	lock_type,
		enum_mdl_type	mdl_type
	)

Add tables from an array to a list of used tables.

Parameters

thd	Current session.
tables	Tables to add.
table_options	A set of the following bits: TL_OPTION_UPDATING : Table will be updated, TL_OPTION_FORCE_INDEX : Force usage of index, TL_OPTION_ALIAS : an alias in multi table DELETE.
lock_type	How table should be locked.
mdl_type	Type of metadata lock to acquire on the table.

Returns: true if error (reported), otherwise false.

◆ agg_func_used()

bool Query_block::agg_func_used ( ) const

inline

◆ all_tables_map()

table_map Query_block::all_tables_map ( ) const

inline

Returns: a map of all tables references in the query block

◆ can_skip_distinct()

bool Query_block::can_skip_distinct ( ) const

inline

Based on the structure of the query at resolution time, it is possible to conclude that DISTINCT is useless and remove it.

This is the case if:

all GROUP BY expressions are in SELECT list, so resulting group rows are distinct,
and ROLLUP is not specified, so it adds no row for NULLs.

Returns: true if we can remove DISTINCT.

◆ cleanup()

void Query_block::cleanup ( bool full )

overridevirtual

Cleanup this subtree (this Query_block and all nested Query_blockes and Query_expressions).

Cleanup after preparation of one round of execution.

Parameters

full	if false only partial cleanup is done, JOINs and JOIN_TABs are kept to provide info for EXPLAIN CONNECTION; if true, complete cleanup is done, all JOINs are freed.

Reimplemented from Query_term.

◆ cleanup_all_joins()

void Query_block::cleanup_all_joins ( )

◆ clone_expression()

Item * Query_block::clone_expression	(	THD *	thd,
		Item *	item,
		Table_ref *	derived_table
	)

Creates a clone for the given expression by re-parsing the expression.

Clone an expression.

Used in condition pushdown to derived tables.

This clone will be used for pushing conditions down to a materialized derived table. Cloning of an expression is done for two purposes:

When the derived table has a query expression with multiple query blocks, each query block involved will be getting a clone of the condition that is being pushed down.
When pushing a condition down to a derived table (with or without unions), columns in the condition are replaced with the derived table's expressions. If there are nested derived tables, these columns will be replaced again with another derived table's expression when the condition is pushed further down. If the derived table expressions are simple columns, we would just keep replacing the original columns with derived table columns. However if the derived table expressions are not simple column references E.g. functions, then columns will be replaced with functions, and arguments to these functions would get replaced when the condition is pushed further down. However, arguments to a function are part of both the SELECT clause of one derived table and the WHERE clause of another derived table where the condition is pushed down (Example below). To keep the sanity of the derived table's expression, a clone is created and used before pushing a condition down.

Ex: Where cloned objects become necessary even when the derived table does not have a UNION.

Consider a query like this one: SELECT * FROM (SELECT i+10 AS n FROM (SELECT a+7 AS i FROM t1) AS dt1 ) AS dt2 WHERE n > 100;

The first call to Query_block::push_conditions_to_derived_tables would result in the following query. "n" in the where clause is replaced with (i+10). SELECT * FROM (SELECT i+10 AS n FROM (SELECT a+7 AS i FROM t1) AS dt1 WHERE (dt1.i+10) > 100) as dt2;

The next call to Query_block::push_conditions_to_derived_tables should result in the following query. "i" is replaced with "a+7". SELECT * FROM (SELECT i+10 AS n FROM (SELECT a+7 AS i FROM t1 WHERE ((t1.a+7)+10) > 100) AS dt1) as dt2;

However without cloned expressions, it would be

SELECT * FROM (SELECT ((t1.a+7)+10) AS n FROM (SELECT a+7 AS i FROM t1 WHERE ((t1.a+7)+10) > 100) AS dt1) as dt2;

Notice that the column "i" in derived table dt2 is getting replaced with (a+7) because the argument of the function in Item_func_plus in (i+10) is replaced with (a+7). The arguments to the function (i+10) need to be different so as to be able to replace them with some other expressions later.

To clone an expression, we re-parse the expression to get another copy and resolve it against the tables of the query block where it will be placed.

Parameters

thd	Current thread
item	Item for which clone is requested
derived_table	derived table to which the item belongs to.

Returns: Cloned object for the item.

◆ cut_subtree()

void Query_block::cut_subtree ( )

inline

◆ debugPrint()

void Query_block::debugPrint	(	int	level,
		std::ostringstream &	buf
	)		const

overridevirtual

Query_term methods overridden.

Implements Query_term.

◆ destroy()

void Query_block::destroy ( )

Destroy contained objects, in particular temporary tables which may have their own mem_roots.

◆ destroy_tree()

void Query_block::destroy_tree ( )

inlineoverridevirtual

Destroy the query term tree structure.

Implements Query_term.

◆ find_table_by_name()

Table_ref * Query_block::find_table_by_name ( const Table_ident * ident )

Finds a (possibly unresolved) table reference in the from clause by name.

There is a hack in the parser which adorns table references with the current database. This function piggy-backs on that hack to find fully qualified table references without having to resolve the name.

Parameters

ident The table name, may be qualified or unqualified.

Return values

NULL	If not found.

◆ first_inner_query_expression()

Query_expression * Query_block::first_inner_query_expression ( ) const

inline

◆ get_derived_expr()

Item * Query_block::get_derived_expr ( uint field_index )

Returns an expression from the select list of the query block using the field's index in a derived table.

Get the expression from this query block using its position in the fields list of the derived table this query block is part of.

Note that the field's position in a derived table does not always reflect the position in the visible field list of the query block. Creation of temporary table for a materialized derived table alters the field position whenever the temporary table adds a hidden field.

Parameters

[in] field_index position in the fields list of the derived table.

Returns: expression from the derived table's query block.

◆ get_fields_list()

mem_root_deque< Item * > * Query_block::get_fields_list ( )

inline

◆ get_in_sum_expr()

uint Query_block::get_in_sum_expr ( ) const

inline

◆ get_limit()

ha_rows Query_block::get_limit ( const THD * thd ) const

Get limit.

Evaluate limit item if necessary.

Returns: Limit of rows in result.

◆ get_number_of_grouping_sets()

int Query_block::get_number_of_grouping_sets ( ) const

inline

◆ get_offset()

ha_rows Query_block::get_offset ( const THD * thd ) const

Get offset for LIMIT.

Evaluate offset item if necessary.

Returns: Number of rows to skip.

◆ get_optimizable_conditions()

bool Query_block::get_optimizable_conditions	(	THD *	thd,
		Item **	new_where,
		Item **	new_having
	)

Returns disposable copies of WHERE/HAVING/ON conditions.

This function returns a copy which can be thrashed during this execution of the statement. Only AND/OR items are trashable! If in conventional execution, no copy is created, the permanent clauses are returned instead, as trashing them is no problem.

Parameters

	thd	thread handle
[out]	new_where	copy of WHERE
[out]	new_having	copy of HAVING (if passed pointer is not NULL)

Copies of join (ON) conditions are placed in Table_ref::m_join_cond_optim.

Returns: true if OOM

◆ get_table_list()

Table_ref * Query_block::get_table_list ( ) const

inline

◆ get_type_str() [1/2]

const char * Query_block::get_type_str ( )

inline

Lookup for a type string.

◆ get_type_str() [2/2]

static const char * Query_block::get_type_str ( enum_explain_type type )

inlinestatic

◆ has_ft_funcs()

bool Query_block::has_ft_funcs ( ) const

inline

Returns: true if query block references full-text functions

◆ has_limit()

bool Query_block::has_limit ( ) const

inline

Returns: true if this query block has a LIMIT clause

◆ has_sj_candidates()

bool Query_block::has_sj_candidates ( ) const

inline

◆ has_subquery_transforms()

bool Query_block::has_subquery_transforms ( ) const

inline

◆ has_tables()

bool Query_block::has_tables ( ) const

inline

Returns: true if query block references any tables

◆ has_windows()

bool Query_block::has_windows ( ) const

inline

Returns: true if query block contains window functions

◆ having_cond()

Item * Query_block::having_cond ( ) const

inline

◆ having_cond_ref()

Item ** Query_block::having_cond_ref ( )

inline

◆ include_chain_in_global()

void Query_block::include_chain_in_global ( Query_block ** start )

Include chain of query blocks into global list.

Parameters

start - Pointer to start of list

◆ include_down()

void Query_block::include_down	(	LEX *	lex,
		Query_expression *	outer
	)

Include query block inside a query expression.

Add this query block below the specified query expression.

Parameters

lex	Containing LEX object
outer	Query expression that query block is added to.

Note: that this query block can never have any underlying query expressions, hence it is not necessary to e.g. renumber those, like e.g. Query_expression::include_down() does.

◆ include_in_global()

void Query_block::include_in_global ( Query_block ** plink )

Include query block into global list.

Parameters

plink - Pointer to start of list

◆ include_neighbour()

void Query_block::include_neighbour	(	LEX *	lex,
		Query_block *	before
	)

Include a query block next to another query block.

Add this query block after the specified query block.

Parameters

lex	Containing LEX object
before	Query block that this object is added after.

◆ include_standalone()

void Query_block::include_standalone ( Query_expression * outer )

Include query block inside a query expression, but do not link.

Include query block within the supplied unit.

Do not link the query block into the global chain of query blocks.

This function is exclusive for Query_expression::add_fake_query_block() - use it with caution.

Parameters

outer Query expression this node is included below.

◆ init_order()

void Query_block::init_order ( )

inline

◆ invalidate()

void Query_block::invalidate ( )

Invalidate by nulling out pointers to other Query_expressions and Query_blockes.

◆ is_cacheable()

bool Query_block::is_cacheable ( ) const

inline

◆ is_dependent()

bool Query_block::is_dependent ( ) const

inline

◆ is_distinct()

bool Query_block::is_distinct ( ) const

inline

Returns: true if this query block contains DISTINCT at start of select list

◆ is_empty_query()

bool Query_block::is_empty_query ( ) const

inline

Returns: true if query block is found during preparation to produce no data. Notice that if query is implicitly grouped, an aggregation row will still be returned.

◆ is_explicitly_grouped()

bool Query_block::is_explicitly_grouped ( ) const

inline

Returns: true if query block is explicitly grouped (non-empty GROUP BY)

◆ is_grouped()

bool Query_block::is_grouped ( ) const

inline

Returns: true if this query block is explicitly or implicitly grouped.

Note: a query with DISTINCT is not considered to be aggregated.; in standard SQL, a query with HAVING is defined as grouped, however MySQL allows HAVING without any aggregation to be the same as WHERE.

◆ is_implicitly_grouped()

bool Query_block::is_implicitly_grouped ( ) const

inline

Returns: true if this query block is implicitly grouped, ie it is not explicitly grouped but contains references to set functions. The query will return max. 1 row (

See also: also is_single_grouped()).

◆ is_non_primitive_grouped()

bool Query_block::is_non_primitive_grouped ( ) const

inline

Returns: true if this query block has GROUP BY modifier.

◆ is_ordered()

bool Query_block::is_ordered ( ) const

inline

Returns: true if this query block contains an ORDER BY clause.

Note: returns false if ORDER BY has been eliminated, e.g if the query can return max. 1 row.

◆ is_recursive()

bool Query_block::is_recursive ( ) const

inline

Returns: true if query block is a recursive member of a recursive unit

◆ is_simple_query_block()

bool Query_block::is_simple_query_block ( ) const

inline

Returns: true when query block is not part of a set operation and is not a parenthesized query expression.

◆ json_agg_func_used()

bool Query_block::json_agg_func_used ( ) const

inline

◆ label_children()

void Query_block::label_children ( )

inlineoverridevirtual

Set the correct value of Query_term::m_sibling_idx recursively for set operations.

For Query_term_unary, this is done in its constructor. A no-op for Query_block. See also set_sibling_idx.

Implements Query_term.

◆ make_active_options()

void Query_block::make_active_options	(	ulonglong	added_options,
		ulonglong	removed_options
	)

Make active options from base options, supplied options and environment:

Make active options from base options, supplied options, any statement options and the environment.

Parameters

added_options	Options that are added to the active options
removed_options	Options that are removed from the active options

◆ mark_as_dependent()

void Query_block::mark_as_dependent	(	Query_block *	last,
		bool	aggregate
	)

Mark all query blocks from this to 'last' as dependent.

Parameters

last	Pointer to last Query_block struct, before which all Query_block are marked as as dependent.
aggregate	true if the dependency is due to a set function, such as COUNT(*), which is aggregated within the query block 'last'. Such functions must have a dependency on all tables of the aggregating query block.

Note: last should be reachable from this Query_block

◆ master_query_expression()

Query_expression * Query_block::master_query_expression ( ) const

inline

◆ next_query_block()

Query_block * Query_block::next_query_block ( ) const

inline

◆ next_select_in_list()

Query_block * Query_block::next_select_in_list ( ) const

inline

◆ open_result_tables()

bool Query_block::open_result_tables	(	THD *	thd,
		int	level
	)

overridevirtual

Open tmp tables for the tree of set operation query results, by recursing.

Parameters

thd	session context
level	level in the tree, top should be called with 0.

Returns: true on error

Reimplemented from Query_term.

◆ operator_string()

const char * Query_block::operator_string ( ) const

inlineoverridevirtual

Get the node type description.

Returns: descriptive string for each node type.

Implements Query_term.

◆ outer_query_block()

Query_block * Query_block::outer_query_block ( ) const

inline

◆ print()

void Query_block::print	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

◆ print_delete()

void Query_block::print_delete	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print detail of the DELETE statement.

Parameters

	thd	Thread handler
[out]	str	String of output
	query_type	Options to print out string output

◆ print_delete_options()

void Query_block::print_delete_options ( String * str )

Print DELETE options.

Parameters

[out] str String of output

◆ print_error()

bool Query_block::print_error	(	const THD *	thd,
		String *	str
	)

Print error.

Parameters

	thd	Thread handler
[out]	str	String of output

Return values

false	If there is no error
true	else

◆ print_from_clause()

void Query_block::print_from_clause	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print list of tables in FROM clause.

Parameters

	thd	Thread handler
[out]	str	String of output
	query_type	Options to print out string output

◆ print_group_by()

void Query_block::print_group_by	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print list of items in GROUP BY clause.

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output

◆ print_having()

void Query_block::print_having	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print list of items in HAVING clause.

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output

◆ print_hints()

void Query_block::print_hints	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print detail of Hints.

Parameters

	thd	Thread handler
[out]	str	String of output
	query_type	Options to print out string output

◆ print_insert()

void Query_block::print_insert	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print detail of the INSERT statement.

Parameters

	thd	Thread handler
[out]	str	String of output
	query_type	Options to print out string output

USES: 'INSERT INTO table (fields) VALUES values' syntax over 'INSERT INTO table SET field = value, ...'

◆ print_insert_fields()

void Query_block::print_insert_fields	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print column list to be inserted into.

Used in INSERT.

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output

◆ print_insert_options()

void Query_block::print_insert_options ( String * str )

Print INSERT options.

Parameters

[out] str String of output

◆ print_item_list()

void Query_block::print_item_list	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print list of items in Query_block object.

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output

Note: that 'INTO variable' clauses are not printed

◆ print_limit()

void Query_block::print_limit	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)		const

◆ print_order_by()

void Query_block::print_order_by	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)		const

Print list of items in ORDER BY clause.

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output

◆ print_qualify()

void Query_block::print_qualify	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)		const

Print list of items in QUALIFY clause.

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output

◆ print_query_block()

void Query_block::print_query_block	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print detail of the Query_block object.

Parameters

	thd	Thread handler
	query_type	Options to print out string output
[out]	str	String of output.

◆ print_select_options()

void Query_block::print_select_options ( String * str )

Print select options.

Parameters

[out] str String of output

◆ print_table_references()

void Query_block::print_table_references	(	const THD *	thd,
		String *	str,
		Table_ref *	table_list,
		enum_query_type	query_type
	)

Print list of tables.

Parameters

	thd	Thread handler
[out]	str	String of output
	table_list	Table_ref object
	query_type	Options to print out string output

◆ print_update()

void Query_block::print_update	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print detail of the UPDATE statement.

Parameters

	thd	Thread handler
[out]	str	String of output
	query_type	Options to print out string output

◆ print_update_list()

void Query_block::print_update_list	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type,
		const mem_root_deque< Item * > &	fields,
		const mem_root_deque< Item * > &	values
	)

Print assignments list.

Used in UPDATE and INSERT ... ON DUPLICATE KEY UPDATE ...

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output
	fields	List columns to be assigned.
	values	List of values.

◆ print_update_options()

void Query_block::print_update_options ( String * str )

Print UPDATE options.

Parameters

[out] str String of output

◆ print_values()

void Query_block::print_values	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type,
		const mem_root_deque< mem_root_deque< Item * > * > &	values,
		const char *	prefix
	)

Print list of values, used in INSERT and for general VALUES clause.

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output
	values	List of values
	prefix	Prefix to print before each row in value list = nullptr: No prefix wanted

◆ print_where_cond()

void Query_block::print_where_cond	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print list of conditions in WHERE clause.

Parameters

	thd	Thread handle
[out]	str	String of output
	query_type	Options to print out string output

◆ print_windows()

void Query_block::print_windows	(	const THD *	thd,
		String *	str,
		enum_query_type	query_type
	)

Print details of Windowing functions.

Parameters

	thd	Thread handler
[out]	str	String of output
	query_type	Options to print out string output

◆ qbPrint()

void Query_block::qbPrint	(	int	level,
		std::ostringstream &	buf
	)		const

Minion of debugPrint.

◆ qualify_cond()

Item * Query_block::qualify_cond ( ) const

inline

◆ qualify_cond_ref()

Item ** Query_block::qualify_cond_ref ( )

inline

◆ query_block()

Query_block * Query_block::query_block ( ) const

inlineoverridevirtual

The query_block which holds the ORDER BY and LIMIT information for this set operation.

Note that for the case where the root is a simple query block, this will return self.

Returns: the query block

Implements Query_term.

◆ query_result()

Query_result * Query_block::query_result ( ) const

inline

◆ remove_base_options()

void Query_block::remove_base_options ( ulonglong options )

inline

Remove base options from a query block.

Active options are also updated, and we assume here that "extra" options cannot override removed base options.

◆ renumber()

void Query_block::renumber ( LEX * lex )

Renumber query blocks of contained query expressions.

Renumber query_block object, and apply renumbering recursively to contained objects.

Parameters

lex	Containing LEX object

◆ restore_cmd_properties()

void Query_block::restore_cmd_properties ( )

Restore prepared statement properties for this query block and all underlying query expressions so they are ready for optimization.

Restores properties saved in Table_ref objects into corresponding TABLEs. Restores ORDER BY and GROUP by clauses, and window definitions, so they are ready for optimization.

◆ right_joins()

bool Query_block::right_joins ( ) const

inline

◆ save_cmd_properties()

bool Query_block::save_cmd_properties ( THD * thd )

Save prepared statement properties for a query block and underlying query expressions.

Required for repeated optimizations of the command.

Parameters

thd	thread handler

Returns: false if success, true if error (out of memory)

◆ save_order_properties()

bool Query_block::save_order_properties	(	THD *	thd,
		SQL_I_List< ORDER > *	list,
		Group_list_ptrs **	list_ptrs
	)

private

Helper for save_properties()

Save properties for ORDER clauses so that they can be reconstructed for a new optimization of the query block.

Parameters

	thd	thread handler
	list	list of ORDER elements to be saved
[out]	list_ptrs	Saved list of ORDER elements

Returns: false if success, true if error (out of memory)

◆ save_properties()

bool Query_block::save_properties ( THD * thd )

Save properties of a prepared statement needed for repeated optimization.

Saves the chain of ORDER::next in group_list and order_list, in case the list is modified by remove_const().

Parameters

thd	thread handler

Returns: false if success, true if error (out of memory)

◆ semijoin_enabled()

bool Query_block::semijoin_enabled ( const THD * thd ) const

Returns whether semi-join is enabled for this query block.

See also: Opt_hints_qb::semijoin_enabled for details on how hints affect this decision. If there are no hints for this query block, optimizer_switch setting determines whether semi-join is used.

Parameters

thd	Pointer to THD object for session. Used to access optimizer_switch

Returns: true if semijoin is enabled, false otherwise

◆ set_agg_func_used()

void Query_block::set_agg_func_used ( bool val )

inline

◆ set_base_options()

void Query_block::set_base_options ( ulonglong options_arg )

inline

Set base options for a query block (and active options too)

◆ set_context()

bool Query_block::set_context ( Name_resolution_context * outer_context )

Assign a default name resolution object for this query block.

Set the name resolution context for the specified query block.

Parameters

outer_context Outer name resolution context. NULL if none or it will be set later.

◆ set_empty_query()

void Query_block::set_empty_query ( )

inline

Set query block as returning no data.

◆ set_having_cond()

void Query_block::set_having_cond ( Item * cond )

inline

◆ set_json_agg_func_used()

void Query_block::set_json_agg_func_used ( bool val )

inline

◆ set_qualify_cond()

void Query_block::set_qualify_cond ( Item * cond )

inline

◆ set_query_result()

void Query_block::set_query_result ( Query_result * result )

inline

◆ set_right_joins()

void Query_block::set_right_joins ( )

inline

◆ set_sj_candidates()

void Query_block::set_sj_candidates ( Mem_root_array< Item_exists_subselect * > * sj_cand )

inline

◆ set_tables_readonly()

void Query_block::set_tables_readonly ( )

inline

Set associated tables as read_only, ie.

they cannot be inserted into, updated or deleted from during this statement. Commonly used for query blocks that are part of derived tables or views that are materialized.

◆ set_where_cond()

void Query_block::set_where_cond ( Item * cond )

inline

◆ setup_base_ref_items()

bool Query_block::setup_base_ref_items ( THD * thd )

Setup the array containing references to base items.

◆ setup_materialize_query_block()

MaterializePathParameters::Operand Query_block::setup_materialize_query_block	(	AccessPath *	child_path,
		TABLE *	dst_table
	)		const

Make materialization parameters for a query block given its input path and destination table,.

Parameters

child_path	the input access path
dst_table	the table to materialize into

Returns: materialization parameter

◆ source_table_is_one_row()

bool Query_block::source_table_is_one_row ( ) const

inline

Returns: true if this query block outputs at most one row.

◆ subquery_strategy()

Subquery_strategy Query_block::subquery_strategy ( const THD * thd ) const

Returns which subquery execution strategies can be used for this query block.

Parameters

thd	Pointer to THD object for session. Used to access optimizer_switch

Return values

SUBQ_MATERIALIZATION	Subquery Materialization should be used
SUBQ_EXISTS	In-to-exists execution should be used
CANDIDATE_FOR_IN2EXISTS_OR_MAT	A cost-based decision should be made

◆ term_type()

Query_term_type Query_block::term_type ( ) const

inlineoverridevirtual

Get the node tree type.

Returns: the tree node type

Implements Query_term.

◆ test_limit()

bool Query_block::test_limit ( )

◆ type()

enum_explain_type Query_block::type ( ) const

Lookup for Query_block type.

◆ update_semijoin_strategies()

void Query_block::update_semijoin_strategies ( THD * thd )

Update available semijoin strategies for semijoin nests.

Available semijoin strategies needs to be updated on every execution since optimizer_switch setting may have changed.

Parameters

thd	Pointer to THD object for session. Used to access optimizer_switch

◆ validate_base_options()

bool Query_block::validate_base_options	(	LEX *	lex,
		ulonglong	options_arg
	)		const

Validate base options for a query block.

Parameters

lex	LEX of current statement
options_arg	base options for a SELECT statement.

Returns: false if success, true if validation failed

These options are supported, per DML statement:

SELECT: SELECT_STRAIGHT_JOIN SELECT_HIGH_PRIORITY SELECT_DISTINCT SELECT_ALL SELECT_SMALL_RESULT SELECT_BIG_RESULT OPTION_BUFFER_RESULT OPTION_FOUND_ROWS OPTION_SELECT_FOR_SHOW DELETE: OPTION_QUICK LOW_PRIORITY INSERT: LOW_PRIORITY HIGH_PRIORITY UPDATE: LOW_PRIORITY

Note that validation is only performed for SELECT statements.

◆ validate_outermost_option()

bool Query_block::validate_outermost_option	(	LEX *	lex,
		const char *	option
	)		const

Check if an option that can be used only for an outer-most query block is applicable to this query block.

Parameters

lex	LEX of current statement
option	option name to output within the error message

Returns: false if valid, true if invalid, error is sent to client

◆ visible_fields() [1/2]

auto Query_block::visible_fields ( )

inline

Wrappers over fields / get_fields_list() that hide items where item->hidden, meant for range-based for loops.

See sql/visible_fields.h.

◆ visible_fields() [2/2]

auto Query_block::visible_fields ( ) const

inline

◆ walk()

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

◆ where_cond()

Item * Query_block::where_cond ( ) const

inline

◆ where_cond_ref()

Item ** Query_block::where_cond_ref ( )

inline

Friends And Related Function Documentation

◆ Condition_context

friend class Condition_context

friend

◆ Query_expression

friend class Query_expression

friend

Member Data Documentation

◆ allow_merge_derived

bool Query_block::allow_merge_derived {true}

private

Allow merge of immediate unnamed derived tables.

◆ base_ref_items

Ref_item_array Query_block::base_ref_items

Array of pointers to "base" items; one each for every selected expression and referenced item in the query block.

All references to fields are to buffers associated with the primary input tables.

◆ between_count

uint Query_block::between_count {0}

Number of between predicates in where/having/on.

◆ cond_count

uint Query_block::cond_count {0}

Number of predicates after preparation.

◆ cond_value

Item::cond_result Query_block::cond_value {Item::COND_UNDEF}

Saved values of the WHERE and HAVING clauses.

Allowed values are:

COND_UNDEF if the condition was not specified in the query or if it has not been optimized yet
COND_TRUE if the condition is always true
COND_FALSE if the condition is impossible
COND_OK otherwise

◆ condition_context

enum_condition_context Query_block::condition_context {enum_condition_context::ANDS}

See also: enum_condition_context

◆ context

Name_resolution_context Query_block::context {}

Context for name resolution for all column references except columns from joined tables.

◆ db

char* Query_block::db {nullptr}

◆ derived_table_count

uint Query_block::derived_table_count {0}

Number of derived tables and views in this query block.

◆ embedding

Table_ref* Query_block::embedding {nullptr}

table embedding the above list

◆ end_lateral_table

Table_ref* Query_block::end_lateral_table {nullptr}

Last table for LATERAL join, used by table functions.

◆ exclude_from_table_unique_test

bool Query_block::exclude_from_table_unique_test {false}

exclude this query block from unique_table() check

◆ fields

mem_root_deque<Item *> Query_block::fields

All expressions needed after join and filtering, ie., select list, group by list, having clause, window clause, order by clause, including hidden fields.

Does not include join conditions nor where clause.

This should ideally be changed into Mem_root_array<Item *>, but find_order_in_list() depends on pointer stability (it stores a pointer to an element in referenced_by[]). Similarly, there are some instances of thd->change_item_tree() that store pointers to elements in this list.

Because of this, adding or removing elements in the middle is not allowed; std::deque guarantees pointer stability only in the face of adding or removing elements from either end, ie., {push,pop}_{front_back}.

Currently, all hidden items must be before all visible items. This is primarily due to the requirement for pointer stability but also because change_to_use_tmp_fields() depends on it when mapping items to ref_item_array indexes. It would be good to get rid of this requirement in the future.

◆ first_context

Name_resolution_context* Query_block::first_context

Pointer to first object in list of Name res context objects that have this query block as the base query block.

Includes field "context" which is embedded in this query block.

◆ first_execution

bool Query_block::first_execution {true}

This variable is required to ensure proper work of subqueries and stored procedures.

Generally, one should use the states of Query_arena to determine if it's a statement prepare or first execution of a stored procedure. However, in case when there was an error during the first execution of a stored procedure, the SP body is not expelled from the SP cache. Therefore, a deeply nested subquery might be left unoptimized. So we need this per-subquery variable to inidicate the optimization/execution state of every subquery. Prepared statements work OK in that regard, as in case of an error during prepare the PS is not created.

◆ ftfunc_list

List<Item_func_match>* Query_block::ftfunc_list

A pointer to ftfunc_list_alloc, list of full text search functions.

◆ ftfunc_list_alloc

List<Item_func_match> Query_block::ftfunc_list_alloc {}

◆ group_fix_field

bool Query_block::group_fix_field {false}

true when GROUP BY fix field called in processing of this query block

◆ group_list

SQL_I_List<ORDER> Query_block::group_list {}

GROUP BY clause.

This list may be mutated during optimization (by remove_const() in the old optimizer or by RemoveRedundantOrderElements() in the hypergraph optimizer), so for prepared statements, we keep a copy of the ORDER.next pointers in group_list_ptrs, and re-establish the original list before each execution. The list can also be temporarily pruned and restored by Group_check (if transform done, cf. Query_block::m_gl_size_orig).

◆ group_list_ptrs

Group_list_ptrs* Query_block::group_list_ptrs {nullptr}

◆ has_aj_nests

bool Query_block::has_aj_nests {false}

private

See also: has_sj_nests; counts antijoin nests.

◆ has_sj_nests

bool Query_block::has_sj_nests {false}

private

True if query block has semi-join nests merged into it.

Notice that this is updated earlier than sj_nests, so check this if info is needed before the full resolver process is complete.

◆ having_fix_field

bool Query_block::having_fix_field {false}

true when having fix field called in processing of this query block

◆ having_value

Item::cond_result Query_block::having_value {Item::COND_UNDEF}

◆ hidden_group_field_count

int Query_block::hidden_group_field_count

private

Number of GROUP BY expressions added to all_fields.

◆ hidden_items_from_optimization

uint Query_block::hidden_items_from_optimization {0}

Hidden items added during optimization.

Note: that using this means we modify resolved data during optimization

◆ hidden_order_field_count

int Query_block::hidden_order_field_count {0}

private

How many expressions are part of the order by but not select list.

◆ in_sum_expr

uint Query_block::in_sum_expr {0}

Parse context: is inside a set function if this is positive.

◆ in_window_expr

uint Query_block::in_window_expr {0}

Parse context: is inside a window function if this is positive.

◆ inner_sum_func_list

Item_sum* Query_block::inner_sum_func_list {nullptr}

Circular linked list of aggregate functions in nested query blocks.

This is needed if said aggregate functions depend on outer values from this query block; if so, we want to add them as hidden items in our own field list, to be able to evaluate them.

See also: Item_sum::check_sum_func

◆ is_item_list_lookup

bool Query_block::is_item_list_lookup {false}

◆ is_table_value_constructor

bool Query_block::is_table_value_constructor {false}

If set, the query block is of the form VALUES row_list.

◆ join

JOIN* Query_block::join {nullptr}

After optimization it is pointer to corresponding JOIN.

This member should be changed only when THD::LOCK_query_plan mutex is taken.

◆ leaf_table_count

uint Query_block::leaf_table_count {0}

Number of leaf tables in this query block.

◆ leaf_tables

Table_ref* Query_block::leaf_tables {nullptr}

Points to first leaf table of query block.

After setup_tables() is done, this is a list of base tables and derived tables. After derived tables processing is done, this is a list of base tables only. Use Table_ref::next_leaf to traverse the list.

◆ link_next

Query_block* Query_block::link_next {nullptr}

private

Intrusive double-linked global list of query blocks.

◆ link_prev

Query_block** Query_block::link_prev {nullptr}

private

◆ linkage

sub_select_type Query_block::linkage {UNSPECIFIED_TYPE}

Describes context of this query block (e.g if it is a derived table).

◆ m_active_options

ulonglong Query_block::m_active_options {0}

private

Active options.

Derived from base options, modifiers added during resolving and values from session variable option_bits. Since the latter may change, active options are refreshed per execution of a statement.

◆ m_added_non_hidden_fields

size_t Query_block::m_added_non_hidden_fields {0}

◆ m_agg_func_used

bool Query_block::m_agg_func_used {false}

private

◆ m_base_options

ulonglong Query_block::m_base_options {0}

private

Options assigned from parsing and throughout resolving, should not be modified after resolving is done.

◆ m_current_table_nest

mem_root_deque<Table_ref *>* Query_block::m_current_table_nest

Pointer to the set of table references in the currently active join.

◆ m_empty_query

bool Query_block::m_empty_query {false}

private

True if query block does not generate any rows before aggregation, determined during preparation (not optimization).

◆ m_having_cond

Item* Query_block::m_having_cond

private

Condition to be evaluated on grouped rows after grouping.

◆ m_internal_limit

bool Query_block::m_internal_limit {false}

If true, limit object is added internally.

◆ m_json_agg_func_used

bool Query_block::m_json_agg_func_used {false}

private

◆ m_no_of_added_exprs

decltype(SQL_I_List<ORDER>::elements) Query_block::m_no_of_added_exprs {0}

For an explicitly grouped, correlated, scalar subquery which is transformed to join with derived tables: the number of added non-column expressions.

Used for better functional dependency analysis since this is checked during prepare after transformations. Transforms will append inner expressions to the group by list, rendering the check too optimistic. To remedy this, we temporarily remove the added compound (i.e. not simple column) expressions when doing the full group by check. This is bit too pessimistic: we can get occasionally false positives (full group by check error). The underlying problem is that we do not perform full group by checking before transformations. See also Group_check's ctor and dtor.

◆ m_num_grouping_sets

int Query_block::m_num_grouping_sets {0}

private

If the query block includes non-primitive grouping, then these modifiers are represented as grouping sets.

The variable 'm_num_grouping_sets' holds the count of grouping sets.

◆ m_qualify_cond

Item* Query_block::m_qualify_cond {nullptr}

private

Condition to be evaluated after window functions.

◆ m_query_result

Query_result* Query_block::m_query_result {nullptr}

private

Result of this query block.

◆ m_right_joins

bool Query_block::m_right_joins {false}

private

True if query block has right joins.

◆ m_saved_base_items

Ref_item_array Query_block::m_saved_base_items

private

A backup of the items in base_ref_items at the end of preparation, so that base_ref_items can be restored between executions of prepared statements.

Empty if it's a regular statement.

◆ m_table_list

SQL_I_List<Table_ref> Query_block::m_table_list {}

List of tables in FROM clause - use Table_ref::next_local to traverse.

◆ m_table_nest

mem_root_deque<Table_ref *> Query_block::m_table_nest

Set of table references contained in outer-most join nest.

◆ m_use_select_limit

bool Query_block::m_use_select_limit {false}

If true, use select_limit to limit number of rows selected.

Applicable when no explicit limit is supplied, and only for the outermost query block of a SELECT statement.

◆ m_was_implicitly_grouped

bool Query_block::m_was_implicitly_grouped {false}

Used by nested scalar_to_derived transformations.

◆ m_where_cond

Item* Query_block::m_where_cond

private

Condition to be evaluated after all tables in a query block are joined.

After all permanent transformations have been conducted by Query_block::prepare(), this condition is "frozen", any subsequent changes to it must be done with change_item_tree(), unless they only modify AND/OR items and use a copy created by Query_block::get_optimizable_conditions(). Same is true for 'having_cond'.

◆ m_windows

List<Window> Query_block::m_windows

All windows defined on the select, both named and inlined.

◆ master

Query_expression* Query_block::master {nullptr}

private

The query expression containing this query block.

◆ materialized_derived_table_count

uint Query_block::materialized_derived_table_count {0}

Number of materialized derived tables and views in this query block.

◆ max_equal_elems

uint Query_block::max_equal_elems {0}

Maximal number of elements in multiple equalities.

◆ n_child_sum_items

uint Query_block::n_child_sum_items {0}

Number of Item_sum-derived objects in children and descendant SELECTs.

◆ n_scalar_subqueries

uint Query_block::n_scalar_subqueries {0}

Keep track for allocation of base_ref_items: scalar subqueries may be replaced by a field during scalar_to_derived transformation.

◆ n_sum_items

uint Query_block::n_sum_items {0}

Number of Item_sum-derived objects in this SELECT.

Keeps count of aggregate functions and window functions(to allocate items in ref array). See Query_block::setup_base_ref_items.

◆ nest_level

int Query_block::nest_level {0}

Nesting level of query block, outer-most query block has level 0, its subqueries have level 1, etc.

See also: also sql/item_sum.h.

◆ next

Query_block* Query_block::next {nullptr}

private

Intrusive linked list of all query blocks within the same query expression.

◆ no_table_names_allowed

bool Query_block::no_table_names_allowed {false}

used for global order by

◆ offset_limit

Item* Query_block::offset_limit {nullptr}

LIMIT ... OFFSET clause, NULL if no offset is given.

◆ olap

olap_type Query_block::olap {UNSPECIFIED_OLAP_TYPE}

Indicates whether this query block contains non-primitive grouping (such as ROLLUP).

◆ opt_hints_qb

Opt_hints_qb* Query_block::opt_hints_qb {nullptr}

Query-block-level hints, for this query block.

◆ order_list

SQL_I_List<ORDER> Query_block::order_list {}

ORDER BY clause.

This list may be mutated during optimization (by remove_const() in the old optimizer or by RemoveRedundantOrderElements() in the hypergraph optimizer), so for prepared statements, we keep a copy of the ORDER.next pointers in order_list_ptrs, and re-establish the original list before each execution.

◆ order_list_ptrs

Group_list_ptrs* Query_block::order_list_ptrs {nullptr}

◆ outer_join

table_map Query_block::outer_join {0}

Bitmap of all inner tables from outer joins.

◆ parent_lex

LEX* Query_block::parent_lex {nullptr}

Reference to LEX that this query block belongs to.

◆ parsing_place

enum_parsing_context Query_block::parsing_place {CTX_NONE}

Parse context: indicates where the current expression is being parsed.

◆ partitioned_table_count

uint Query_block::partitioned_table_count {0}

Number of partitioned tables.

◆ recursive_reference

Table_ref* Query_block::recursive_reference {nullptr}

If this query block is a recursive member of a recursive unit: the Table_ref, in this recursive member, referencing the query name.

◆ resolve_nest

Table_ref* Query_block::resolve_nest

Initial value:

{

nullptr}

Used when resolving outer join condition.

◆ resolve_place

Resolve_place Query_block::resolve_place

Initial value:

{

RESOLVE_NONE}

Query_block::RESOLVE_NONE

@ RESOLVE_NONE

Definition: sql_lex.h:2075

Indicates part of query being resolved.

◆ rollup_group_items

Prealloced_array<Item_rollup_group_item *, 4> Query_block::rollup_group_items

Initial value:

{

PSI_NOT_INSTRUMENTED}

PSI_NOT_INSTRUMENTED

#define PSI_NOT_INSTRUMENTED

Definition: validate_password_imp.cc:42

◆ rollup_sums

Prealloced_array<Item_rollup_sum_switcher *, 4> Query_block::rollup_sums

Initial value:

{

PSI_NOT_INSTRUMENTED}

◆ row_value_list

mem_root_deque<mem_root_deque<Item *> *>* Query_block::row_value_list {nullptr}

The VALUES items of a table value constructor.

◆ saved_cond_count

uint Query_block::saved_cond_count {0}

Number of arguments of and/or/xor in where/having/on.

◆ select_limit

Item* Query_block::select_limit {nullptr}

LIMIT clause, NULL if no limit is given.

◆ select_list_tables

table_map Query_block::select_list_tables {0}

The set of those tables whose fields are referenced in the select list of this select level.

◆ select_n_having_items

uint Query_block::select_n_having_items {0}

Number of items in the select list, HAVING clause, QUALIFY clause and ORDER BY clause.

It is used to reserve space in the base_ref_items array so that it is big enough to hold hidden items for any of the expressions or sub-expressions in those clauses.

◆ select_n_where_fields

uint Query_block::select_n_where_fields {0}

Number of fields used in select list or where clause of current select and all inner subselects.

◆ select_number

uint Query_block::select_number {0}

Query block number (used for EXPLAIN)

◆ sj_candidates

Mem_root_array<Item_exists_subselect *>* Query_block::sj_candidates {nullptr}

private

Pointer to collection of subqueries candidate for semi/antijoin conversion.

Template parameter is "true": no need to run DTORs on pointers.

◆ sj_nests

mem_root_deque<Table_ref *> Query_block::sj_nests

List of semi-join nests generated for this query block.

◆ sj_pullout_done

bool Query_block::sj_pullout_done {false}

True when semi-join pull-out processing is complete.

◆ skip_local_transforms

bool Query_block::skip_local_transforms {false}

True: skip local transformations during prepare() call (used by INSERT)

◆ slave

Query_expression* Query_block::slave {nullptr}

private

The first query expression contained within this query block.

◆ subquery_in_having

bool Query_block::subquery_in_having {false}

HAVING clause contains subquery => we can't close tables before query processing end even if we use temporary table.

◆ table_func_count

uint Query_block::table_func_count {0}

Number of table functions in this query block.

◆ type_str

const char * Query_block::type_str

staticprivate

Initial value:

= {"NONE",          "PRIMARY",
                                          "SIMPLE",        "DERIVED",
                                          "SUBQUERY",      "UNION",
                                          "INTERSECT",     "EXCEPT",
                                          "UNION RESULT",  "INTERSECT RESULT",
                                          "EXCEPT RESULT", "RESULT" ,
                                          "MATERIALIZED"}

Note: The order of the elements of this array must correspond to the order of elements in enum_explain_type.

◆ uncacheable

uint8 Query_block::uncacheable {0}

result of this query can't be cached, bit field, can be : UNCACHEABLE_DEPENDENT UNCACHEABLE_RAND UNCACHEABLE_SIDEEFFECT

◆ with_sum_func

bool Query_block::with_sum_func {false}

True if contains or aggregates set functions.

Note: this is wrong when a locally found set function is aggregated in an outer query block.

◆ with_wild

uint Query_block::with_wild {0}

Number of wildcards used in the SELECT list.

For example, SELECT *, t1.*, catalog.t2.* FROM t0, t1, t2; has 3 wildcards.

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

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Private Member Functions

Private Attributes

Static Private Attributes

Friends

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ Resolve_place

Constructor & Destructor Documentation

◆ Query_block()

Member Function Documentation

◆ absorb_limit_of()

◆ accept()

◆ active_options()

◆ add_active_options()

◆ add_base_options()

◆ add_ftfunc_to_list()

◆ add_item_to_list()

◆ add_subquery_transform_candidate()

◆ add_tables()

◆ agg_func_used()

◆ all_tables_map()

◆ can_skip_distinct()

◆ cleanup()

◆ cleanup_all_joins()

◆ clone_expression()

◆ cut_subtree()

◆ debugPrint()

◆ destroy()

◆ destroy_tree()

◆ find_table_by_name()

◆ first_inner_query_expression()

◆ get_derived_expr()

◆ get_fields_list()

◆ get_in_sum_expr()

◆ get_limit()

◆ get_number_of_grouping_sets()

◆ get_offset()

◆ get_optimizable_conditions()

◆ get_table_list()

◆ get_type_str() [1/2]

◆ get_type_str() [2/2]

◆ has_ft_funcs()

◆ has_limit()

◆ has_sj_candidates()

◆ has_subquery_transforms()

◆ has_tables()

◆ has_windows()

◆ having_cond()

◆ having_cond_ref()

◆ include_chain_in_global()

◆ include_down()

◆ include_in_global()

◆ include_neighbour()

◆ include_standalone()

◆ init_order()

◆ invalidate()

◆ is_cacheable()

◆ is_dependent()

◆ is_distinct()

◆ is_empty_query()

◆ is_explicitly_grouped()

◆ is_grouped()

◆ is_implicitly_grouped()

◆ is_non_primitive_grouped()

◆ is_ordered()

◆ is_recursive()

◆ is_simple_query_block()

◆ json_agg_func_used()

◆ label_children()

◆ make_active_options()

◆ mark_as_dependent()

◆ master_query_expression()

◆ next_query_block()

◆ next_select_in_list()

◆ open_result_tables()