SQL語句

Oracle的EMP表,查詢每一個部門工資前三名的員工信息，如何寫？？ 
解答：（通用sql）

from emp e1
where
   (
    select count(1)
    from emp e2
    where e2.deptno=e1.deptno and e2.sal>=e1.sal
   ) <=3 /*這裏的數值表示你想取前幾名*/
order by deptno, sal desc;

Oracle查詢：（利用分區功能） 

(select deptno,ename,sal,row_number() over (partition by deptno
    order by sal desc) rn
from emp)
   where rn<3;