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