select t2.dept_no, max(emp_no), t2.maxSalaries from
(select t1.dept_no, salaries.emp_no, t1.maxSalaries from salaries join
(select dept_no, emp_no, max(salary) as maxSalaries from dept_emp join salaries using (emp_no)
group by dept_no) as t1
on salaries.salary = t1.maxSalaries
order by dept_no) as t2
group by dept_no
order by dept_no

隐藏条件是emp_no要取最大的,服。debug了半天