changes in row operation

mysql-test/r/subselect.result

@@ -923,7 +923,7 @@ select a, (select a,b,c from t1 where t1.a=t2.a) = ROW(a,2,'a'),(select c from t
 a	(select a,b,c from t1 where t1.a=t2.a) = ROW(a,2,'a')	(select c from t1 where a=t2.a)
 1	1	a
 2	0	b
-NULL	NULL	NULL
+NULL	0	NULL
 select a, (select a,b,c from t1 where t1.a=t2.a) = ROW(a,3,'b'),(select c from t1 where a=t2.a) from t2;
 a	(select a,b,c from t1 where t1.a=t2.a) = ROW(a,3,'b')	(select c from t1 where a=t2.a)
 1	0	a
@@ -933,7 +933,7 @@ select a, (select a,b,c from t1 where t1.a=t2.a) = ROW(a,4,'c'),(select c from t
 a	(select a,b,c from t1 where t1.a=t2.a) = ROW(a,4,'c')	(select c from t1 where a=t2.a)
 1	0	a
 2	0	b
-NULL	NULL	NULL
+NULL	0	NULL
 drop table t1,t2;
 create table t1 (a int, b real, c varchar(10));
 insert into t1 values (1, 1, 'a'), (2,2,'b'), (NULL, 2, 'b');