单行子查询返回多行。

select empno,sal,deptno,row_number()over(partition by deptno order by sal desc) 部门薪资排名,
sum(sal)over(partition by deptno) 部门总工资 from emp
where (select row_number()over(partition by deptno order by sal desc) from emp)<=3;

想表达啥