select xm from (select xm from t_ygjbxx where rownum<10 order by xm)
minus
select xm from (select xm from t_ygjbxx where rownum<5 order by xm)
minus
select xm from (select xm from t_ygjbxx where rownum<5 order by xm)
minus
select c1 from (select c1 from t1 order by c1) where rownum<5;
(select c1 from t1 where rownum<10
minus
select c1 from t1 where rownum<5)
order by c1
select c1 from (select c1 from t1 order by c1) where rownum<10
minus
select c1 from (select c1 from t1 order by c1) where rownum<5;