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(date) AS day, COUNT(*) AS question_cnt
FROM question_practice_detail
WHERE date BETWEEN '2021-08-01' AND '2021-08-31'
GROUP BY day
ORDER BY day;
关键语法
DAY(date)：提取 date 字段的“天”部分。COUNT(*)：计算每天的练习题目数量。WHERE date BETWEEN '2021-08-01' AND '2021-08-31'：筛选 2021 年 8 月的数据。GROUP BY day：按天分组，统计每天的题目数。ORDER BY day：按日期升序排列结果。