Query_result_union Class Reference

#include <sql_union.h>

Inheritance diagram for Query_result_union:

Public Member Functions
	Query_result_union ()
bool	prepare (THD *thd, List< Item > &list, SELECT_LEX_UNIT *u) override
	Perform preparation specific to the query expression or DML statement. More...
virtual bool	postponed_prepare (THD *thd, List< Item > &types)
	Do prepare() if preparation has been postponed until column type information is computed (used by Query_result_union_direct). More...
bool	send_data (THD *thd, List< Item > &items) override
bool	send_eof (THD *thd) override
virtual bool	flush ()
void	cleanup (THD *) override
	Cleanup after this execution. More...
bool	reset () override
	Reset and empty the temporary table that stores the materialized query result. More...
bool	create_result_table (THD *thd, List< Item > *column_types, bool is_distinct, ulonglong options, const char *alias, bool bit_fields_as_long, bool create_table)
	Create a temporary table to store the result of a query expression (used, among others, when materializing a UNION DISTINCT). More...
virtual const ha_rows *	row_count () const override
Public Member Functions inherited from Query_result_interceptor
	Query_result_interceptor ()
uint	field_count (List< Item > &) const override
bool	send_result_set_metadata (THD *, List< Item > &, uint) override
bool	is_interceptor () const override 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 ()
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	optimize ()
	Optimize the result processing of a query expression, applicable to data change operation (not simple select queries). More...
virtual bool	start_execution (THD *)
	Prepare for execution of the query expression or DML statement. More...
virtual void	send_error (THD *, uint errcode, const char *err)
virtual bool	check_simple_select () const
	Check if this query returns a result set and therefore is allowed in cursors and set an error message if it is not the case. More...
virtual void	abort_result_set (THD *)
void	begin_dataset ()

Public Attributes
TABLE *	table
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...

Private Attributes
Temp_table_param	tmp_table_param
ha_rows	m_rows_in_table
	Count of rows successfully stored in tmp table. More...

Friends
bool	TABLE_LIST::create_materialized_table (THD *thd)

Additional Inherited Members
Protected Attributes inherited from Query_result
SELECT_LEX_UNIT *	unit

Constructor & Destructor Documentation

Query_result_union()

Query_result_union::Query_result_union ( )

inline

Member Function Documentation

cleanup()

void Query_result_union::cleanup ( THD *  )

inlineoverridevirtual

Cleanup after this execution.

Completes the execution and resets object before next execution of a prepared statement/stored procedure.

Reimplemented from Query_result.

create_result_table()

bool Query_result_union::create_result_table	(	THD *	thd_arg,
		List< Item > *	column_types,
		bool	is_union_distinct,
		ulonglong	options,
		const char *	table_alias,
		bool	bit_fields_as_long,
		bool	create_table
	)

Create a temporary table to store the result of a query expression (used, among others, when materializing a UNION DISTINCT).

Parameters

thd_arg	thread handle
column_types	a list of items used to define columns of the temporary table
is_union_distinct	if set, the temporary table will eliminate duplicates on insert
options	create options
table_alias	name of the temporary table
bit_fields_as_long	convert bit fields to ulonglong
create_table	If false, a table handler will not be created when creating the result table.

Create a temporary table that is used to store the result of a UNION, derived table, or a materialized cursor.

Returns

false if table created, true if error

flush()

bool Query_result_union::flush ( )

virtual

Reimplemented in Query_result_union_direct.

postponed_prepare()

virtual bool Query_result_union::postponed_prepare ( THD *  thd, List< Item > &  types  )

inlinevirtual

Do prepare() if preparation has been postponed until column type information is computed (used by Query_result_union_direct).

Parameters

thd	Thread handle
types	Column types

Returns

false on success, true on failure

Reimplemented in Query_result_union_direct.

prepare()

bool Query_result_union::prepare ( THD *  , List< Item > &  , SELECT_LEX_UNIT *  u  )

overridevirtual

Perform preparation specific to the query expression or DML statement.

Returns

false if success, true if error

Reimplemented from Query_result.

reset()

bool Query_result_union::reset ( )

overridevirtual

Reset and empty the temporary table that stores the materialized query result.

Note

The cleanup performed here is exactly the same as for the two temp tables of JOIN - exec_tmp_table_[1 | 2].

Reimplemented from Query_result.

row_count()

virtual const ha_rows* Query_result_union::row_count ( ) const

inlineoverridevirtual

Returns

Pointer to count of rows retained by this result.

Reimplemented from Query_result.

send_data()

bool Query_result_union::send_data ( THD *  thd, List< Item > &  items  )

overridevirtual

Implements Query_result.

send_eof()

bool Query_result_union::send_eof ( THD *  thd )

overridevirtual

Implements Query_result.

Friends And Related Function Documentation

TABLE_LIST::create_materialized_table

bool TABLE_LIST::create_materialized_table ( THD *  thd )

friend

Member Data Documentation

m_rows_in_table

ha_rows Query_result_union::m_rows_in_table

private

Count of rows successfully stored in tmp table.

table

TABLE* Query_result_union::table

tmp_table_param

Temp_table_param Query_result_union::tmp_table_param

private

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

• sql/sql_union.h
• sql/sql_union.cc