题解 | #计算用户8月每天的练题数量#
计算用户8月每天的练题数量
https://www.nowcoder.com/practice/847373e2fe8d47b4a2c294bdb5bda8b6
SELECT DAY(q.date) AS day, COUNT(q.device_id) AS question_cnt FROM question_practice_detail AS q WHERE MONTH(q.date) = 8 AND YEAR(q.date) = 2021 GROUP BY q.date;
属于分类聚合查询,故需要加入分组语句。