Commit e81337d8 authored by unknown's avatar unknown
Browse files

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

into  linux.site:/home/reggie/bk/bug7403
parents 0589559e 0f41fb42

mysql-test/r/select.result

+11 −0
Original line number Diff line number Diff line
@@ -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;

mysql-test/t/select.test

+11 −0
Original line number Diff line number Diff line
@@ -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;

sql/sql_select.cc

+19 −1
Original line number Diff line number Diff line
@@ -3509,6 +3509,22 @@ inline void add_cond_and_fix(Item **e1, Item *e2) 
      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;