题解 | #月均完成试卷数不小于3的用户爱作答的类别#
月均完成试卷数不小于3的用户爱作答的类别
https://www.nowcoder.com/practice/b1d13efcfa0c4ecea517afbdb9090845
SELECT tag, COUNT(start_time) AS tag_cnt FROM exam_record JOIN examination_info USING(exam_id) WHERE uid IN (SELECT uid FROM (SELECT uid, DATE_FORMAT(submit_time,'%Y%m') AS month, COUNT(submit_time) AS cnt FROM exam_record JOIN examination_info USING(exam_id) GROUP BY uid,DATE_FORMAT(submit_time,'%Y%m') HAVING cnt >= 3 )t1) GROUP BY tag ORDER BY tag_cnt DESC LIMIT 3;