MySQL：按日期范围分组

Question

假设我们有一个包含id, title, status, expires_at, created_at列的Products表。

我可以通过指定所有参数来获取一周的值：

SELECT
    count(id)
FROM 
    products
WHERE
    status = 'APPROVED' AND
    expires_at >= '2018-09-10 09:00:00' AND
    created_at <= '2018-09-10 09:00:00' AND
    deleted_at IS NULL;

我们如何运行按1 - 52年的几周对产品进行分组的查询-每周在哪里显示未过期的产品： created_at <= week-end AND expires_at <= week-end或active ：

Active_Products | Week_Of_Year 
----------------|---------------
274             | 2018-01
----------------|---------------
1011            | 2018-02
----------------|---------------
180             | 2018-03
----------------|---------------
990             | 2018-04
----------------|---------------
765             | 2018-05

我已使用SQL小提琴更新了此问题： http ://sqlfiddle.com/#!9/ e4830b/4

Answer 1

通过计算星期开始日期和结束日期尝试以下查询

select week(expires_at),count(id) as active_products
from product
where expires_at>SUBDATE(expires_at, weekday(expires_at)) and expires_at<DATE(expires_at + INTERVAL (6 - WEEKDAY(expires_at)) DAY)
group by week(expires_at)

Answer 2

我相信您希望给定星期内的活动产品的逻辑更像*created_at* >= week-start AND expires_at < week-end 。

如果您在所有星期中都创建了产品，则可以使用相关的子查询：

select week_of_year,
       (select count(*)
        from products t2
        where yearweek(t2.created_at) >= w.week_of_year and
              yearweek(t2.expires_at) < w.week_of_year
       ) as num_actives
from (select distinct yearweek(created_at) as week_of_year
      from products
     ) w;

Answer 3

您可以使用函数YEARWEEK(date) （ https://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_yearweek ）以可读的方式显示星期数包括年份 （yyyymm）。

SELECT 
count(id) as active_products, YEARWEEK(expires_at)
FROM products
GROUP BY YEARWEEK(expires_at)

使用WEEK()不会影响同一周的年份。