题解 | #浙大不同难度题目的正确率#
浙大不同难度题目的正确率
http://www.nowcoder.com/practice/d8a4f7b1ded04948b5435a45f03ead8c
select qd.difficult_level, sum(if(qpd.result='right',1,0)) / count(qpd.result) as correct_rate from question_practice_detail as qpd left join question_detail as qd on qd.question_id = qpd.question_id LEFT JOIN user_profile as up on up.device_id = qpd.device_id where up.university = '浙江大学' GROUP by qd.difficult_level order by correct_rate
