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
http://www.nowcoder.com/practice/f4714f7529404679b7f8909c96299ac4
我是这样做的宝子们
count(qpd.question_id) / count(distinct qpd.device_id) as avg_answer_cnt
from user_profile as up
inner join question_practice_detail as qpd
on up.device_id = qpd.device_id
inner join question_detail as qd
on qpd.question_id = qd.question_id
where university="山东大学"
group by university,difficult_level
查看9道真题和解析
投递北森等公司10个岗位