SELECT d.`dept_no`,d.`dept_name`,b.`title`,COUNT(b.`title`) as count FROM( (`dept_emp` a INNER JOIN `titles` b ON a.`emp_no` = b.`emp_no` ) INNER JOIN `departments` d ON d.`dept_no` = a.`dept_no` ) GROUP BY b.`title`,d.`dept_no`,d.`dept_name` ORDER BY d.`dept_no`,b.`title`; 越来越熟练了!!!