Commit e81337d8 authored by unknown's avatar unknown

Merge rburnett@bk-internal.mysql.com:/home/bk/mysql-4.1

into  linux.site:/home/reggie/bk/bug7403

parents 0589559e 0f41fb42
......@@ -2559,3 +2559,14 @@ WHERE
COUNT(*)
4
drop table t1,t2,t3;
create table t1 (f1 int);
insert into t1 values (1),(NULL);
create table t2 (f2 int, f3 int, f4 int);
create index idx1 on t2 (f4);
insert into t2 values (1,2,3),(2,4,6);
select A.f2 from t1 left join t2 A on A.f2 = f1 where A.f3=(select min(f3)
from t2 C where A.f4 = C.f4) or A.f3 IS NULL;
f2
1
NULL
drop table t1,t2;
......@@ -2116,3 +2116,14 @@ WHERE
drop table t1,t2,t3;
#
# Bug #11482 4.1.12 produces different resultset for a complex query
# than in previous 4.1.x
create table t1 (f1 int);
insert into t1 values (1),(NULL);
create table t2 (f2 int, f3 int, f4 int);
create index idx1 on t2 (f4);
insert into t2 values (1,2,3),(2,4,6);
select A.f2 from t1 left join t2 A on A.f2 = f1 where A.f3=(select min(f3)
from t2 C where A.f4 = C.f4) or A.f3 IS NULL;
drop table t1,t2;
......@@ -3508,7 +3508,23 @@ inline void add_cond_and_fix(Item **e1, Item *e2)
(where othertbl is a non-const table and othertbl.field may be NULL)
and add them to conditions on correspoding tables (othertbl in this
example).
Exception from that is the case when referred_tab->join != join.
I.e. don't add NOT NULL constraints from any embedded subquery.
Consider this query:
SELECT A.f2 FROM t1 LEFT JOIN t2 A ON A.f2 = f1
WHERE A.f3=(SELECT MIN(f3) FROM t2 C WHERE A.f4 = C.f4) OR A.f3 IS NULL;
Here condition A.f3 IS NOT NULL is going to be added to the WHERE
condition of the embedding query.
Another example:
SELECT * FROM t10, t11 WHERE (t10.a < 10 OR t10.a IS NULL)
AND t11.b <=> t10.b AND (t11.a = (SELECT MAX(a) FROM t12
WHERE t12.b = t10.a ));
Here condition t10.a IS NOT NULL is going to be added.
In both cases addition of NOT NULL condition will erroneously reject
some rows of the result set.
referred_tab->join != join constraint would disallow such additions.
This optimization doesn't affect the choices that ref, range, or join
optimizer make. This was intentional because this was added after 4.1
was GA.
......@@ -3539,6 +3555,8 @@ static void add_not_null_conds(JOIN *join)
DBUG_ASSERT(item->type() == Item::FIELD_ITEM);
Item_field *not_null_item= (Item_field*)item;
JOIN_TAB *referred_tab= not_null_item->field->table->reginfo.join_tab;
if (referred_tab->join != join)
continue;
Item *notnull;
if (!(notnull= new Item_func_isnotnull(not_null_item)))
DBUG_VOID_RETURN;
......
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