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Fixed bug #15347: Wrong result of subselect when records cache and set

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functions are involved.

When subselect is a join with set functions and no record have been found in
it, end_send_group() sets null_row for all tables in order aggregate functions 
to calculate their values correctly. Normally this null_row flag is cleared for 
each table in sub_select(), but flush_cached_records() doesn't do so.
Due to this all fields from the table processed by flush_cached_records() are 
always evaluated as nulls and whole select produces wrong result.

flush_cached_records() now clears null_row flag at the very beginning.
This commit is contained in:
evgen@moonbone.local
2006-01-11 23:16:21 +03:00
parent c8000f437d
commit 3e23d458f9
3 changed files with 25 additions and 0 deletions
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11
mysql-test/r/select.result
View File

@@ -3337,3 +3337,14 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 const PRIMARY PRIMARY 4 const 1 Using index 1 SIMPLE t2 const PRIMARY PRIMARY 4 const 1 Using index
1 SIMPLE t3 const PRIMARY PRIMARY 8 const,const 1 1 SIMPLE t3 const PRIMARY PRIMARY 8 const,const 1
DROP TABLE t1,t2,t3; DROP TABLE t1,t2,t3;
create table t1 (f1 int);
insert into t1 values(1),(2);
create table t2 (f2 int, f3 int, key(f2));
insert into t2 values(1,1),(2,2);
create table t3 (f4 int not null);
insert into t3 values (2),(2),(2);
select f1,(select count(*) from t2,t3 where f2=f1 and f3=f4) as count from t1;
f1 count
1 0
2 3
drop table t1,t2,t3;

13
mysql-test/t/select.test
View File

@@ -2805,3 +2805,16 @@ EXPLAIN SELECT t2.key_a,foo
WHERE t2.key_a=2 and key_b=5; WHERE t2.key_a=2 and key_b=5;
DROP TABLE t1,t2,t3; DROP TABLE t1,t2,t3;
#
# Bug#15347 Wrong result of subselect when records cache and set functions
# are involved
#
create table t1 (f1 int);
insert into t1 values(1),(2);
create table t2 (f2 int, f3 int, key(f2));
insert into t2 values(1,1),(2,2);
create table t3 (f4 int not null);
insert into t3 values (2),(2),(2);
select f1,(select count(*) from t2,t3 where f2=f1 and f3=f4) as count from t1;
drop table t1,t2,t3;

1
sql/sql_select.cc
View File

@@ -9853,6 +9853,7 @@ flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skip_last)
int error; int error;
READ_RECORD *info; READ_RECORD *info;
join_tab->table->null_row= 0;
if (!join_tab->cache.records) if (!join_tab->cache.records)
return NESTED_LOOP_OK; /* Nothing to do */ return NESTED_LOOP_OK; /* Nothing to do */
if (skip_last) if (skip_last)