select up.device_id,university, count(qpd.question_id) as question_cnt, sum(if(qpd.result='right',1,0)) as right_question_cnt from user_profile up left join question_practice_detail qpd on up.device_id = qpd.device_id and month( qpd.date)=8 or null where university='复旦大学'group by up.device_id ;