题解 | #统计作答次数#
统计作答次数
https://www.nowcoder.com/practice/45a87639110841b6950ef6a12d20175f
# 统计出总作答次数total_pv、 # 试卷已完成作答数complete_pv、 # 已完成的试卷数complete_exam_cnt。 SELECT COUNT(id) AS total_pv, COUNT(score) AS complete_pv, (SELECT COUNT(DISTINCT exam_id) FROM exam_record WHERE score IS NOT NULL )AS complete_exam_cnt FROM exam_record