还是考察窗口函数的应用
select
tt.dept_no,
tt.emp_no,
tt.salary
from (
select
t1.* ,t2.salary
,row_number()over(partition by dept_no order by salary desc) as rn
from dept_emp t1
left JOIN salaries t2
on t1.emp_no = t2.emp_no) tt
where rn =1
order by
tt.dept_no,
tt.emp_no