题解 | 统计每个用户的平均刷题数
统计每个用户的平均刷题数
https://www.nowcoder.com/practice/f4714f7529404679b7f8909c96299ac4
select
u.university,
qd.difficult_level,
round(
count(qpd.question_id) / count(distinct qpd.device_id),
4
) as avg_answer_cnt
from
user_profile u
join question_practice_detail qpd on u.device_id = qpd.device_id
join question_detail qd on qpd.question_id = qd.question_id
where
u.university = '山东大学'
group by
u.university,
qd.difficult_level;
