select
    dept_no,
    emp_no,
    salary maxSalary
from (
select
    d.emp_no emp_no,
    d.dept_no dept_no,
    s.salary salary,
    rank() over(partition by d.dept_no order by s.salary desc) rk
from dept_emp d join salaries s on d.emp_no = s.emp_no
) a
where a.rk=1
order by dept_no;