Hi!
create table t1 (
n number,
v varchar2(2)
);
create table t2 (
n number,
v varchar2(2)
);
insert into t1 values (1, 'a1');
insert into t2 values (1, 'a1');
insert into t2 values (1, 'a2');
insert into t2 values (1, 'a3');
insert into t2 values (2, 'a1');
insert into t2 values (2, 'a2');
insert into t2 values (3, 'a1');
commit;
select * from t1 join t2 on t1.n=t2.n and rownum=1;
N V
- --
1 a1
select * from t1 LEFT join t2 on t1.n=t2.n and rownum=1;
N V
- --
1 a1
1 a1
1 a1
Why the second query returns 3 rows? ROWNUM seems to be ignored.
Explain me that, please. I'm now aware of some "inside things", probably.