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
sum(if(qpd.result = 'right', 1, 0) as right_question_cnt)
select up.device_id, up.university,
count(question_id) as question_cnt,
sum(if(qpd.result = 'right', 1, 0)) as right_question_cnt
from user_profile up
left join question_practice_detail qpd
on qpd.device_id = up.device_id and month(qpd.date) = 8
where up.university = '复旦大学'
group by up.device_id
