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 t1.university
,count(t2.question_id)/count(distinct t1.device_id) as avg_answer_cnt
from user_profile t1
join question_practice_detail t2
on t1.device_id = t2.device_id
group by t1.university
,count(t2.question_id)/count(distinct t1.device_id) as avg_answer_cnt
from user_profile t1
join question_practice_detail t2
on t1.device_id = t2.device_id
group by t1.university
