select dept_no,emp_no,Salary salary
from(
select dept_no,emp_no,Salary,row_number()over(partition by dept_no order by Salary desc) as rn
from(
select  dept_no,emp_no ,sum(salary) Salary
from dept_emp join  salaries using(emp_no)
group by dept_no,emp_no
)t1
)t2
where rn =1