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 b.tag,count(*) tag_cnt from exam_record a join examination_info b on a.exam_id=b.exam_id and a.uid in (select a.uid z from exam_record a join examination_info b on a.exam_id=b.exam_id group by a.uid,LEFT(submit_time,7) having count(a.submit_time)>=3) group by b.tag order by tag_cnt desc