创建两个表再连接

创建表1：员工-部门-薪资表
表2：部门-部门最高薪资表
再根据部门连接两个表即可

select a.dept_no, a.emp_no, b.maxSalary
from 
(select a.emp_no, a.dept_no, b.salary
from dept_emp as a inner join salaries as b
on a.emp_no = b.emp_no
) as a
inner join
(select dept_no, max(salary) as maxSalary
from dept_emp as a inner join salaries as b
on a.emp_no = b.emp_no
group by dept_no
) as b
on a.dept_no = b.dept_no and a.salary = b.maxSalary
order by a.dept_no