with f as (
    select d.dept_no, d.emp_no, s.salary
    from dept_emp d left join salaries s on d.emp_no = s.emp_no
)

select 
    a.dept_no, a.emp_no, b.salary
from 
    (select * from f) as a, 
    (select dept_no, max(salary) "salary"
     from f group by dept_no) as b
where a.dept_no = b.dept_no and a.salary = b.salary
order by a.dept_no