## 6、取得平均薪水最高的部门的部门名称  思路 1.链接两张表 select * from emp e inner join dept d on e.deptno=d.deptno 2.分组看各部门薪水 select e.deptno,max(d.dname),avg(sal) from emp e inner join dept d on e.deptno=d.deptno group by e.deptno 3.排序 select e.deptno,max(d.dname),avg(sal) from emp e inner join dept d on e.deptno=d.deptno group by e.deptno order by avg(sal) desc 4.取得薪水最高的部门 select e.deptno,max(d.dname),avg(sal) from emp e inner join dept d on e.deptno=d.deptno group by e.deptno order by avg(sal) desc limit 0,1