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 difficult_level, AVG(IF(qpd.result = 'right', 1, 0)) correct_rate FROM user_profile up INNER JOIN question_practice_detail qpd ON up.device_id = qpd.device_id INNER JOIN question_detail qd ON qpd.question_id = qd.question_id WHERE up.university = '浙江大学' GROUP BY qd.difficult_level ORDER BY correct_rate;