题解 | #统计作答次数#
统计作答次数
https://www.nowcoder.com/practice/45a87639110841b6950ef6a12d20175f
select count(start_time) total_pv, count(submit_time) complete_pv, (select count(distinct exam_id) from ( select distinct exam_id,start_time,submit_time from exam_record where submit_time is not null order by 1 asc)a) from exam_record
