SELECT
    a.staff_id,
    a.staff_name,
    CONCAT(
        ROUND(b.dock_salary/normal_salary * 100.0,1)
        ,'%') AS dock_ratio
FROM staff_tb AS a
INNER JOIN salary_tb AS b
    ON (a.staff_id = b.staff_id)
WHERE a.department = 'dep1'
ORDER BY dock_ratio DESC;