Item_sum_count Class Reference

Inheritance diagram for Item_sum_count:

List of all members.

Public Member Functions
	Item_sum_count (Item *item_par)
	Item_sum_count (List< Item > &list)
	Item_sum_count (THD *thd, Item_sum_count *item)
enum Sumfunctype	sum_func () const
void	no_rows_in_result ()
void	make_const (longlong count_arg)
longlong	val_int ()
void	reset_field ()
void	update_field ()
const char *	func_name () const
Item *	copy_or_same (THD *thd)
Friends
class	Aggregator_distinct

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Constructor & Destructor Documentation

Item_sum_count::Item_sum_count

(

List< Item > &

list

)

[inline]

Constructs an instance for COUNT(DISTINCT)

Parameters:

list	a list of the arguments to the aggregate function

This constructor is called by the parser only for COUNT (DISTINCT).

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Member Function Documentation

void Item_sum_count::no_rows_in_result

(

)

[inline, virtual]

Mark an aggregate as having no rows.

This function is called by the execution engine to assign 'NO ROWS FOUND' value to an aggregate item, when the underlying result set has no rows. Such value, in a general case, may be different from the default value of the item after 'clear()': e.g. a numeric item may be initialized to 0 by clear() and to NULL by no_rows_in_result().

Reimplemented from Item_sum.

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

• item_sum.h
• item_sum.cc