从排序后的结果集中删除前n条记录

端午有人休息，有人忙

操作前数据：

--从排序后的结果集中删除前n条记录
delete from emp
where empno in (select empno
                   from (select *
                           from emp
                          where comm is not null
                            and rownum < &n
                          order by hiredate desc))