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 q.device_id) AS avg_answer_cnt
FROM user_profile
JOIN question_practice_detail q
USING(device_id)
GROUP BY university;
