- 求平均薪水的等级最低的部门的部门名称
select dname from dept
join
(select deptno, grade from
(select deptno, avg(sal) avg_sal from emp group by deptno) t
join salgrade
on (t.avg_sal between salgrade.losal and salgrade.hisal)
) t
on dept.deptno = t.deptno
where t.grade =
(select min(grade) from
(select avg(sal) avg_sal from emp group by deptno) t
join salgrade
on (t.avg_sal between salgrade.losal and salgrade.hisal)
);
思路都是求出部门的平均薪水等级,然后利用min()求出平均薪水等级最低的部门,这里有个疑问,如果平均薪水最低的有两个,那么这个min(),只能返回一条数据,这个查询结果不是错的吗,应该怎么解决呢