题解 | #筛选限定昵称成就值活跃日期的用户#

WITH a1 AS (
           SELECT uid, question_id, submit_time AS start_time, submit_time
           FROM practice_record
           UNION ALL
           SELECT uid, exam_id, start_time, submit_time
           FROM exam_record
           )#连接试卷和答题表
SELECT uid, nick_name, achievement
FROM user_info JOIN a1 USING (uid)
WHERE nick_name LIKE '牛客%号'
  AND achievement BETWEEN 1200 AND 2500 #筛选出符合题意的用户
GROUP BY uid
HAVING MAX(DATE_FORMAT(start_time,'%Y%m')) = '202109'#筛选出202109最近登陆的用户