select
dept_no,
emp_no,
salary
from 
(
    select
    dept_no,
    de.emp_no,
    salary,
    row_number()over(partition by dept_no order by salary desc) rn
    from dept_emp as de
    join salaries as s on de.emp_no = s.emp_no
) a
where rn = 1
order by dept_no asc;