题解 | #未完成试卷数大于1的有效用户#
未完成试卷数大于1的有效用户
https://www.nowcoder.com/practice/46cb7a33f7204f3ba7f6536d2fc04286
select uid, count(if(submit_time is null, 1, null)) incomplete_cnt, count(if(submit_time is null, null, 1)) complete_cnt, group_concat(distinct concat_ws(':',date_format(start_time, '%Y-%m-%d'), tag) separator ';') detail from exam_record er join examination_info ei on er.exam_id = ei.exam_id where year(start_time) = '2021' group by uid having count(if(submit_time is null, 1, null))>1 and count(if(submit_time is null, 1, null))<5 and count(if(submit_time is null, null, 1))>=1 order by count(if(submit_time is null, 1, null)) desc;