WITH basis AS
(SELECT dept_name, emp_no, first_name, last_name, salary,
        RANK() OVER (PARTITION BY dept_name
                         ORDER BY salary DESC) ranks
   FROM dept_emp_sal_v
),
top10 AS
(SELECT *
   FROM basis
  WHERE ranks <= 10
)
 SELECT dept_name, emp_no, first_name, last_name, salary,
        NTILE(3) OVER (PARTITION BY dept_name
                           ORDER BY salary DESC) grade
   FROM top10
  ORDER BY 1, 6;