题解 | #统计复旦用户8月练题情况#
统计复旦用户8月练题情况
http://www.nowcoder.com/practice/53235096538a456b9220fce120c062b3
select al.device_id,al.university,
count(some.device_id) as question_cnt,
count(case when some.result="right" then some.device_id end) as right_question_cnt
from(select device_id,university from user_profile where university="复旦大学")as al
left join question_practice_detail as some
on some.device_id=al.device_id
group by device_id
单独给她点个赞
查看12道真题和解析