题解 | #统计作答次数#
统计作答次数
http://www.nowcoder.com/practice/45a87639110841b6950ef6a12d20175f
SELECT COUNT(start_time) total_pv,COUNT(submit_time) complete_pv,(SELECT COUNT(DISTINCT exam_id) FROM exam_record WHERE submit_time IS NOT NULL) omplete_exam_cnt FROM exam_record;