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, # round(count(q.question_id)/count(distinct(q.device_id)),4) as avg_answer_cnt # from user_profile as u, question_practice_detail as q # where u.device_id = q.device_id # group by u.university; select university, round(count(q.question_id)/count(distinct(q.device_id)),4) as avg_answer_cnt from user_profile u join question_practice_detail q on u.device_id = q.device_id group by u.university;
