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(a.device_id) / count(distinct a.device_id) as avg_answer_cnt
from
user_profile a
right join question_practice_detail b
on a.device_id = b.device_id
group by
university