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 university, COUNT(question_id)/COUNT(DISTINCT user_profile.device_id) AS avg_answer_cnt FROM user_profile INNER JOIN question_practice_detail WHERE user_profile.device_id = question_practice_detail.device_id GROUP BY university ORDER BY university ASC