mysql - 过去 5 天按天分组

Question

我正在尝试选择过去 5 天的整数字段的总和，我需要将它分组为每一天。

我在确定分组时遇到了一些问题。到目前为止，这是我的 sql 查询:

select 
    sum(`amount_sale`) as total 
from `sales` 
where the_date >= unix_timestamp((CURDATE() - INTERVAL 5 DAY))

这可以很好地生成所有 5 天的总和，但我需要将其分解，以便它显示过去 5 天中每一天的总和，即:

day 1 - $200

day 2- $500

day 3 - $20

等等

Answer 1

SELECT  DATE(FROM_UNIXTIME(the_date)) AS dt, SUM(amount_sale) AS total
FROM    sales
WHERE   the_date >= UNIX_TIMESTAMP((CURDATE() - INTERVAL 5 DAY))
GROUP BY
        dt

要为缺少的日期返回 0:

SELECT  dt, COALESCE(SUM(amount_sale), 0) AS total
FROM    (
        SELECT  CURDATE() - INTERVAL 1 DAY AS dt
        UNION ALL
        SELECT  CURDATE() - INTERVAL 2 DAY AS dt
        UNION ALL
        SELECT  CURDATE() - INTERVAL 3 DAY AS dt
        UNION ALL
        SELECT  CURDATE() - INTERVAL 4 DAY AS dt
        UNION ALL
        SELECT  CURDATE() - INTERVAL 5 DAY AS dt
        ) d
LEFT JOIN
        sales
ON      the_date >= UNIX_TIMESTAMP(dt)
        AND the_date < UNIX_TIMESTAMP(dt + INTERVAL 1 DAY)
GROUP BY
        dt

这不是一个非常优雅的解决方案，但是，MySQL 缺少一种从头开始生成记录集的方法。