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 u.university, count(question_id)/count(distinct(q.device_id)) avg_answer_cnt from user_profile u join question_practice_detail q on u.device_id = q.device_id group by university;
