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,
round(
count(q.question_id) / count(distinct q.device_id),
4
) as avg_answer_cnt
from
user_profile u
right join question_practice_detail q on u.device_id = q.device_id
group by
university
order by
university
题干重点：答过题的平均用户答题数，B表是答题用户和答题明细，所以以B表为主表进行查询
