d.dept_no,d.emp_no,d.salary maxSalary
from(select
*,row_number()over(partition by c.dept_no order by c.salary desc) rt
from (select a.dept_no,a.emp_no,b.salary
from dept_emp a
inner join salaries b
on a.emp_no=b.emp_no)c) d
where d.rt=1