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(*) / COUNT(DISTINCT qpd.device_id)
FROM user_profile
JOIN question_practice_detail qpd
USING (device_id)
GROUP BY university
ORDER BY university
