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 a.device_id,
a.university,
count(question_id) as question_cnt,
sum(
if(result = "right",1,0)
) as right_question_cnt
from user_profile a left join question_practice_detail b on a.device_id=b.device_id and month(b.date)='08'
where a.university = "复旦大学"
group by a.device_id
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