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
https://www.nowcoder.com/practice/d8a4f7b1ded04948b5435a45f03ead8c
select c.difficult_level, sum(if(b.result='right',1,0)) / count(b.question_id) as correct_rate from question_detail c join question_practice_detail b using(question_id) join user_profile a using(device_id) where a.university = '浙江大学' group by c.difficult_level order by correct_rate
呜呜困难题我居然自己写出来了!!!