题解 | 统计加班员工占比

SELECT T3.department,CONCAT(ROUND(SUM(work_hour)/COUNT(work_hour)*100,1),'%') AS ratio
FROM (SELECT T2.department,IF(TIMESTAMPDIFF(minute,first_clockin,last_clockin)/60 >9.5,1,0) AS work_hour 
FROM attendent_tb T1 LEFT JOIN staff_tb T2 ON T1.staff_id=T2.staff_id) AS T3
GROUP BY department ORDER BY ratio DESC