#include <parse_tree_nodes.h>

Inheritance diagram for PT_query_expression:

Public Member Functions
	PT_query_expression (const POS &pos, PT_with_clause with_clause, PT_query_expression_body body, PT_order order, PT_limit_clause limit)

	PT_query_expression (const POS &pos, PT_query_expression_body body, PT_order order, PT_limit_clause *limit)

	PT_query_expression (const POS &pos, PT_query_expression_body *body)

bool	do_contextualize (Parse_context *pc) override

bool	is_set_operation () const override

bool	has_into_clause () const override

bool	has_trailing_into_clause () const override

bool	can_absorb_order_and_limit (bool order, bool limit) const override
	True if this query expression can absorb an extraneous order by/limit clause. More...

bool	is_table_value_constructor () const override

PT_insert_values_list *	get_row_value_list () const override

Public Member Functions inherited from PT_query_expression_body
	PT_query_expression_body (const POS &pos)

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

bool	is_contextualized () const

virtual bool	contextualize (Context *pc) final

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

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

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

Private Member Functions
bool	contextualize_order_and_limit (Parse_context *pc)
	Contextualizes the order and limit clauses, re-interpreting them according to the rules. More...

Private Attributes
PT_query_expression_body *	m_body

PT_order *	m_order

PT_limit_clause *	m_limit

PT_with_clause *	m_with_clause

Additional Inherited Members
Public Types inherited from Parse_tree_node_tmpl< Context >
typedef Context	context_t

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

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

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

Public Attributes inherited from Parse_tree_node_tmpl< Context >
POS	m_pos

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

	Parse_tree_node_tmpl (const POS &pos)

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

bool	begin_parse_tree (Show_parse_tree *tree)

bool	end_parse_tree (Show_parse_tree *tree)

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

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

Constructor & Destructor Documentation

◆ PT_query_expression() [1/3]

PT_query_expression::PT_query_expression	(	const POS &	pos,
		PT_with_clause *	with_clause,
		PT_query_expression_body *	body,
		PT_order *	order,
		PT_limit_clause *	limit
	)

inline

◆ PT_query_expression() [2/3]

PT_query_expression::PT_query_expression	(	const POS &	pos,
		PT_query_expression_body *	body,
		PT_order *	order,
		PT_limit_clause *	limit
	)

inline

◆ PT_query_expression() [3/3]

PT_query_expression::PT_query_expression	(	const POS &	pos,
		PT_query_expression_body *	body
	)

inlineexplicit

Member Function Documentation

◆ can_absorb_order_and_limit()

bool PT_query_expression::can_absorb_order_and_limit	(	bool	order,
		bool	limit
	)		const

inlineoverridevirtual

True if this query expression can absorb an extraneous order by/limit clause.

The ORDER BY/LIMIT syntax is mostly consistestent, i.e. a trailing clause may not refer to the tables in the <query primary>, with one glaring exception:

(...( SELECT ... )...) ORDER BY ...

If the nested query expression doesn't contain ORDER BY, the statement is interpreted as if the ORDER BY was absorbed by the innermost query expression, i.e.:

(...( SELECT ... ORDER BY ... )...)

There is no rewriting of the parse tree nor AST happening here, the transformation is done by the contextualizer (see PT_query_expression::contextualize_order_and_limit), which interprets the parse tree, and builds the AST according to this interpretation. This interpretation is governed by the following rule: An ORDER BY can be absorbed if none the nested query expressions contains an ORDER BY or LIMIT. The rule is complex, so here are some examples for illustration:

In these cases the ORDER BY is absorbed:

( SELECT * FROM t1 ) ORDER BY t1.a;
(( SELECT * FROM t1 )) ORDER BY t1.a;

In these cases the ORDER BY is not absorbed:

( SELECT * FROM t1 ORDER BY 1 ) ORDER BY t1.a;
(( SELECT * FROM t1 ) ORDER BY 1 ) ORDER BY t1.a;
( SELECT * FROM t1 LIMIT 1 ) ORDER BY t1.a;
(( SELECT * FROM t1 ) LIMIT 1 ) ORDER BY t1.a;

The same happens with LIMIT, obviously, but the optimizer is freeer to choose when to apply the limit, and there are name no resolution issues involved.

Parameters

order	True if the outer query block has the ORDER BY clause.
limit	True if the outer query block has the LIMIT clause.

Implements PT_query_expression_body.

◆ contextualize_order_and_limit()

bool PT_query_expression::contextualize_order_and_limit ( Parse_context * pc )

private

Contextualizes the order and limit clauses, re-interpreting them according to the rules.

If the <query expression body> can absorb the clauses, they are simply contextualized into the current Query_block. If not, we have to create the "fake" Query_block unless there is one already (Query_expression::new_set_operation_query() is known to do this.)

See also: PT_query_expression::can_absorb_order_and_limit()

◆ do_contextualize()

bool PT_query_expression::do_contextualize ( Parse_context * pc )

override

◆ get_row_value_list()

PT_insert_values_list * PT_query_expression::get_row_value_list ( ) const

inlineoverridevirtual

Implements PT_query_expression_body.

◆ has_into_clause()

bool PT_query_expression::has_into_clause ( ) const

inlineoverridevirtual

Implements PT_query_expression_body.

◆ has_trailing_into_clause()

bool PT_query_expression::has_trailing_into_clause ( ) const

inlineoverridevirtual

Implements PT_query_expression_body.

◆ is_set_operation()

bool PT_query_expression::is_set_operation ( ) const

inlineoverridevirtual

Implements PT_query_expression_body.

◆ is_table_value_constructor()

bool PT_query_expression::is_table_value_constructor ( ) const

inlineoverridevirtual

Implements PT_query_expression_body.

Member Data Documentation

◆ m_body

PT_query_expression_body* PT_query_expression::m_body

private

◆ m_limit

PT_limit_clause* PT_query_expression::m_limit

private

◆ m_order

PT_order* PT_query_expression::m_order

private

◆ m_with_clause

PT_with_clause* PT_query_expression::m_with_clause

private

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

sql/parse_tree_nodes.h
sql/parse_tree_nodes.cc

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ PT_query_expression() [1/3]

◆ PT_query_expression() [2/3]

◆ PT_query_expression() [3/3]

Member Function Documentation

◆ can_absorb_order_and_limit()

◆ contextualize_order_and_limit()

◆ do_contextualize()

◆ get_row_value_list()

◆ has_into_clause()

◆ has_trailing_into_clause()

◆ is_set_operation()

◆ is_table_value_constructor()

Member Data Documentation

◆ m_body

◆ m_limit

◆ m_order

◆ m_with_clause