Question

假设我们有一个posts表，其中包含以下列：id, title, expires_at。我们想要显示每年每周都没有“过期”的帖子数量。

也许更简单的方法是：“按一年中的几周分组的帖子数量expires_at日期很好，然后是每周的开始”

例如：

-------------------------------------------------
|   Year    |   Week    |   posts_not_expired   |
------------|-----------|-----------------------|
|   2017    |   01      |   22                  |
|   2017    |   02      |   103                 |
|   2017    |   03      |   7                   |
|   ...     |   ...     |   ...                 |
|   2009    |   52      |   63                  |
|-----------|-----------|-----------------------|

到目前为止我们有什么：

SELECT
    COUNT(id) as posts_not_expired,
    YEAR(expires_at) * 100 as Year,
    YEARWEEK(expires_at) as Week,
FROM posts
GROUP BY Year, Week

Answer 1

您可以使用DAYOFWEEK计算给定周的未过期帖子。（其中1 =星期日，2 =星期一，... 7 =星期六）

SELECT
    YEAR(expires_at) as `Year`,
    WEEKOFYEAR(expires_at) as `Week`,
    SUM(DAYOFWEEK(expires_at) > 2) as `posts_not_expired`
FROM posts
GROUP BY YEAR(expires_at), WEEKOFYEAR(expires_at)

MYSQL：按周间隔分组，其中大于星期一

1 个答案: