题解 | 统计有未完成状态的试卷的未完成数和未完成率
统计有未完成状态的试卷的未完成数和未完成率
https://www.nowcoder.com/practice/69fc2b1df4144c0991e4b8280d8aba27
with a as (select distinct exam_id from exam_record where submit_time is null) select exam_id, count(case when submit_time is null then 1 else null end) as incomplete_cnt, round(count(case when submit_time is null then 1 else null end)/count(*) ,3) from exam_record where exam_id in (select exam_id from a) group by exam_id
