Commit c872b005 authored by unknown's avatar unknown
Browse files

Fix for bug #21976: Unnecessary warning with count(decimal) 

We use val_int() calls (followed by null_value check) to determine 
nullness in some Item_sum_count' and Item_sum_count_distinct' methods, 
as a side effect we get extra warnings raised in the val_int().
Fix: use is_null() instead.


mysql-test/r/func_group.result:
  Fix for bug #21976: Unnecessary warning with count(decimal)
    - test result.
mysql-test/t/func_group.test:
  Fix for bug #21976: Unnecessary warning with count(decimal)
    - test case.
sql/item.h:
  Fix for bug #21976: Unnecessary warning with count(decimal)
    - comment adjusted.
sql/item_sum.cc:
  Fix for bug #21976: Unnecessary warning with count(decimal)
    - use is_null() to determine nullness.
parent 6cf0571a

mysql-test/r/func_group.result

+10 −0
Original line number Diff line number Diff line
@@ -1029,3 +1029,13 @@ t1 CREATE TABLE `t1` ( 
  `stddev(0)` double(8,4) default NULL

) ENGINE=MyISAM DEFAULT CHARSET=latin1

drop table t1;

create table t1 (a decimal(20));

insert into t1 values (12345678901234567890);

select count(a) from t1;

count(a)

1

select count(distinct a) from t1;

count(distinct a)

1

drop table t1;

End of 5.0 tests

mysql-test/t/func_group.test

+11 −0
Original line number Diff line number Diff line
@@ -700,3 +700,14 @@ create table t1 select stddev(0); 
show create table t1;

drop table t1;

 

#

# Bug #21976: Unnecessary warning with count(decimal)

#



create table t1 (a decimal(20));

insert into t1 values (12345678901234567890);

select count(a) from t1;

select count(distinct a) from t1;

drop table t1;



--echo End of 5.0 tests

sql/item.h

+5 −6
Original line number Diff line number Diff line
@@ -701,12 +701,11 @@ class Item { 
  virtual bool get_date_result(TIME *ltime,uint fuzzydate)

  { return get_date(ltime,fuzzydate); }

  /*

    This function is used only in Item_func_isnull/Item_func_isnotnull

    (implementations of IS NULL/IS NOT NULL clauses). Item_func_is{not}null

    calls this method instead of one of val/result*() methods, which

    normally will set null_value. This allows to determine nullness of

    a complex expression without fully evaluating it.

    Any new item which can be NULL must implement this call.

    The method allows to determine nullness of a complex expression 

    without fully evaluating it, instead of calling val/result*() then 

    checking null_value. Used in Item_func_isnull/Item_func_isnotnull

    and Item_sum_count/Item_sum_count_distinct.

    Any new item which can be NULL must implement this method.

  */

  virtual bool is_null() { return 0; }

sql/item_sum.cc

+5 −27
Original line number Diff line number Diff line
@@ -1034,14 +1034,8 @@ void Item_sum_count::clear() 


bool Item_sum_count::add()

{

  if (!args[0]->maybe_null)

  if (!args[0]->maybe_null || !args[0]->is_null())

    count++;

  else

  {

    (void) args[0]->val_int();

    if (!args[0]->null_value)

      count++;

  }

  return 0;

}
@@ -1941,14 +1935,8 @@ void Item_sum_count::reset_field() 
  char *res=result_field->ptr;

  longlong nr=0;



  if (!args[0]->maybe_null)

    nr=1;

  else

  {

    (void) args[0]->val_int();

    if (!args[0]->null_value)

  if (!args[0]->maybe_null || !args[0]->is_null())

    nr=1;

  }

  int8store(res,nr);

}
@@ -2051,14 +2039,8 @@ void Item_sum_count::update_field() 
  char *res=result_field->ptr;



  nr=sint8korr(res);

  if (!args[0]->maybe_null)

    nr++;

  else

  {

    (void) args[0]->val_int();

    if (!args[0]->null_value)

  if (!args[0]->maybe_null || !args[0]->is_null())

    nr++;

  }

  int8store(res,nr);

}
@@ -2531,13 +2513,9 @@ bool Item_sum_count_distinct::setup(THD *thd) 
    Item *item=args[i];

    if (list.push_back(item))

      return TRUE;                              // End of memory

    if (item->const_item())

    {

      (void) item->val_int();

      if (item->null_value)

    if (item->const_item() && item->is_null())

      always_null= 1;

  }

  }

  if (always_null)

    return FALSE;

  count_field_types(tmp_table_param,list,0);