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
用case的办法，case换if能更简单一些。
SELECT t1.device_id AS device_id, ANY_VALUE(t1.university) AS university, SUM(CASE WHEN t1.device_id IN (t2.device_id) THEN 1 ELSE 0 END), SUM(CASE WHEN t1.device_id IN (t2.device_id) AND t2.result = 'right' THEN 1 ELSE 0 END) FROM user_profile AS t1 LEFT JOIN question_practice_detail AS t2 ON t1.device_id = t2.device_id AND MONTH (date) = 8 WHERE university = '复旦大学' GROUP BY device_id
这样才显得专业