drop table t1; create table t1 (c1 char(2) primary key, c2 char(1) not null); insert into t1 values (‘A ‘,‘A‘); select t1.c1 from t1 where t1.c1 in (select c2 from t1 union all select ‘0‘||c2 c2 from t1);
select /*+ full(t1) */ t1.c1 from t1 where t1.c1 in (select c2 from t1 union all select ‘0‘||c2 c2 from t1); 1st query returns no row, 2nd query return ‘A‘