Query_result_null Class Reference

A query result handler that outputs nothing. More...

Inheritance diagram for Query_result_null:

Public Member Functions
	Query_result_null ()
uint	field_count (const mem_root_deque< Item * > &) const override
bool	send_result_set_metadata (THD *, const mem_root_deque< Item * > &, uint) override
bool	send_data (THD *thd, const mem_root_deque< Item * > &items) override
bool	send_eof (THD *) override
Public Member Functions inherited from Query_result_interceptor
	Query_result_interceptor ()
uint	field_count (const mem_root_deque< Item * > &) const override
bool	send_result_set_metadata (THD *, const mem_root_deque< Item * > &, uint) override
bool	is_interceptor () const final
	Checks if this Query_result intercepts and transforms the result set. More...
Public Member Functions inherited from Query_result
	Query_result ()
virtual	~Query_result ()=default
virtual bool	needs_file_privilege () const
virtual bool	change_query_result (THD *, Query_result *)
	Change wrapped Query_result. More...
virtual bool	need_explain_interceptor () const
virtual bool	prepare (THD *, const mem_root_deque< Item * > &, Query_expression *u)
	Perform preparation specific to the query expression or DML statement. More...
virtual bool	start_execution (THD *)
	Prepare for execution of the query expression or DML statement. More...
virtual bool	create_table_for_query_block (THD *)
	Create table, only needed to support CREATE TABLE ... SELECT. More...
virtual bool	check_supports_cursor () const
	Check if this query result set supports cursors. More...
virtual void	abort_result_set (THD *)
virtual bool	reset ()
	Cleanup after one execution of the unit, to be ready for a next execution inside the same statement. More...
virtual void	cleanup ()
	Cleanup after this execution. More...
virtual void	set_limit (ha_rows)
	Only overridden (and non-empty) for Query_result_union, q.v. More...
virtual Server_side_cursor *	cursor () const

Private Attributes
String	m_str

Additional Inherited Members
Public Attributes inherited from Query_result
ha_rows	estimated_rowcount
	Number of records estimated in this result. More...
double	estimated_cost
	Cost to execute the subquery which produces this result. More...
Protected Attributes inherited from Query_result
Query_expression *	unit

Detailed Description

A query result handler that outputs nothing.

It is used during EXPLAIN ANALYZE, to ignore the output of the query when it's being run.

Constructor & Destructor Documentation

Query_result_null()

Query_result_null::Query_result_null ( )

inline

Member Function Documentation

field_count()

uint Query_result_null::field_count ( const mem_root_deque< Item * > &  ) const

inlineoverridevirtual

Reimplemented from Query_result.

send_data()

bool Query_result_null::send_data ( THD *  thd, const mem_root_deque< Item * > &  items  )

inlineoverridevirtual

Implements Query_result.

send_eof()

bool Query_result_null::send_eof ( THD *  )

inlineoverridevirtual

Implements Query_result.

send_result_set_metadata()

bool Query_result_null::send_result_set_metadata ( THD *  , const mem_root_deque< Item * > &  , uint    )

inlineoverridevirtual

Implements Query_result.

Member Data Documentation

m_str

String Query_result_null::m_str

private

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

• sql/opt_explain.cc