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
https://www.nowcoder.com/practice/53235096538a456b9220fce120c062b3
SELECT
user_profile.device_id,
university,
SUM(IF(MONTH(date) = 8,1,0)) AS question_cnt,
SUM(IF(result = 'right' AND MONTH(date) = 8,1,0)) AS right_question_cnt
FROM
user_profile LEFT JOIN question_practice_detail
ON user_profile.device_id = question_practice_detail.device_id
WHERE
user_profile.university = '复旦大学'
GROUP BY
device_id
?
