Select c.dept_no, c.emp_no, maxSalary
FROM
(SELECT a.dept_no as dept_no, a.emp_no as emp_no, b.salary as maxSalary, max(b.salary) over (partition by a.dept_no) as salary
From dept_emp as a
left join salaries as b
on a.emp_no = b.emp_no) as c
where maxSalary = c.salary

思路：

首先利用窗口函数 max() 找出每个部门中的最大值当作一列

然后Select工资等于max那一列的工资即可