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MDEV-9550 COUNT(NULL) returns incorrect result with sequence storage engine

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when calculating COUNT(basic_const), take into account that
this basic_const may be NULL
This commit is contained in:
Sergei Golubchik 2016-02-22 12:52:29 +01:00
commit e6d51aac77
3 changed files with 18 additions and 3 deletions
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8
storage/sequence/mysql-test/sequence/group_by.result
View file

@ -85,4 +85,10 @@ id select_type table type possible_keys key key_len ref rows Extra
explain select count(*) from seq_1_to_15_step_2 group by mod(seq,2);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE seq_1_to_15_step_2 index NULL PRIMARY 8 NULL 8 Using index; Using temporary; Using filesort
drop table seq_1_to_15_step_2;
create temporary table t1 select * from seq_1_to_3;
select count(NULL) from t1;
count(NULL)
0
select count(NULL) from seq_1_to_3;
count(NULL)
0

7
storage/sequence/mysql-test/sequence/group_by.test
View file

@ -39,4 +39,9 @@ explain select count(*) from seq_1_to_15_step_2, seq_1_to_15_step_2 as t2;
explain select count(*) from seq_1_to_15_step_2 where seq > 0;
explain select count(*) from seq_1_to_15_step_2 group by mod(seq,2);
drop table seq_1_to_15_step_2;
#
# MDEV-9550 COUNT(NULL) returns incorrect result with sequence storage engine
#
create temporary table t1 select * from seq_1_to_3;
select count(NULL) from t1;
select count(NULL) from seq_1_to_3;

6
storage/sequence/sequence.cc
View file

@ -452,7 +452,11 @@ int ha_seq_group_by_handler::next_row()
switch (item_sum->sum_func()) {
case Item_sum::COUNT_FUNC:
{
field->store((longlong) elements, 1);
Item *arg0= ((Item_sum*) item_sum)->get_arg(0);
if (arg0->basic_const_item() && arg0->is_null())
field->store(0LL, 1);
else
field->store((longlong) elements, 1);
break;
}
case Item_sum::SUM_FUNC: