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))
--4 行被删除,耗时 0.015 秒
操作后数据

以此记录
原文:http://www.cnblogs.com/iyoume2008/p/6920829.html