题解 | #统计作答次数#
统计作答次数
https://www.nowcoder.com/practice/45a87639110841b6950ef6a12d20175f
select count(a.start_time) total_pv, count(a.submit_time) complete_v, count(distinct case when score is null then null else exam_id end ) as complete_exam_cnt from exam_record a