select department, concat ( round( sum( case when work_time > 9.5 then 1 else 0 end ) / count(staff_id) * 100, 1 ), '%' ) ratio from ( select staff_id, round( timestampdiff (minute, first_clockin, last_clockin) / 60, 1 ) work_time from attendent_tb ) t join staff_tb using (staff_id) group by depa...