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
up.university,
qd.difficult_level,
round(count(qpd.question_id) / count(distinct qpd.device_id), 4) as avg_answer_cnt
from
question_detail as qd
inner join question_practice_detail as qpd on qpd.question_id = qd.question_id
inner join user_profile as up on qpd.device_id = up.device_id
where up.university ='山东大学'
group by
qd.difficult_level
order by
qd.difficult_level;
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