select dept_no, s.emp_no, salary as max_Salary
from salaries s
join dept_emp de
on s.emp_no = de.emp_no
where (dept_no, salary) in (
    select dept_no, max(salary)
    from salaries s
    join dept_emp de
    on s.emp_no = de.emp_no
    where s.to_date = '9999-01-01'
    group by dept_no
)
order by dept_no