题解 | #统计每个学校的答过题的用户的平均答题数#
统计每个学校的答过题的用户的平均答题数
https://www.nowcoder.com/practice/88aa923a9a674253b861a8fa56bac8e5
select T1.university, ( count(T2.question_id) / count(distinct T2.device_id) ) as avg_each_q from user_profile T1, question_practice_detail T2 where T1.device_id = T2.device_id group by university;
Mark一下。