题解 | #试卷发布当天作答人数和平均分#
试卷发布当天作答人数和平均分
https://www.nowcoder.com/practice/5b58e89556dc4153a79d8cf8c08ba499
SELECT r.exam_id,COUNT(DISTINCT r.uid) uv,ROUND(AVG(r.score),1) avg_score FROM exam_record r LEFT JOIN user_info u ON r.uid=u.uid RIGHT JOIN examination_info i ON r.exam_id=i.exam_id WHERE u.level>5 AND i.tag='SQL' AND DATE_FORMAT(r.start_time,'%Y%m')=DATE_FORMAT(i.release_time,'%Y%m') GROUP BY r.exam_id ORDER BY COUNT(DISTINCT r.uid) DESC,ROUND(AVG(r.score),1)
