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Item_sum_count Class Reference
Inheritance diagram for Item_sum_count:
Item_sum_int Item_sum_num Item_sum Item_result_field Item

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
Itemcopy_or_same (THD *thd)


class Aggregator_distinct

Constructor & Destructor Documentation

Item_sum_count::Item_sum_count ( List< Item > &  list) [inline]

Constructs an instance for COUNT(DISTINCT)

lista list of the arguments to the aggregate function

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

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.

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