mysql - 按日期聚合日期范围内的数据，结果集中没有日期间隙

Question

我有一个包含卖单的表格，我想列出两个日期之间每天的 COUNT 个卖单，且不留日期间隙。

这是我目前拥有的:

SELECT COUNT(*) as Norders, DATE_FORMAT(date, "%M %e") as sdate 
FROM ORDERS 
WHERE date <= NOW() 
  AND date >= NOW() - INTERVAL 1 MONTH 
GROUP BY DAY(date) 
ORDER BY date ASC;

我得到的结果如下:

6     May 1
14    May 4
1     May 5
8     Jun 2
5     Jun 15

但是我想要得到的是:

6     May 1
0     May 2
0     May 3
14    May 4
1     May 5
0     May 6
0     May 7
0     May 8
.....
0     Jun 1
8     Jun 2
.....
5     Jun 15

这可能吗？

Answer 1

动态创建一系列日期并将其加入到您的订单表中:-

SELECT sub1.sdate, COUNT(ORDERS.id) as Norders
FROM
(
    SELECT DATE_FORMAT(DATE_SUB(NOW(), INTERVAL units.i + tens.i * 10 + hundreds.i * 100 DAY), "%M %e") as sdate 
    FROM (SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9)units
    CROSS JOIN (SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9)tens
    CROSS JOIN (SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9)hundreds
    WHERE DATE_SUB(NOW(), INTERVAL units.i + tens.i * 10 + hundreds.i * 100 DAY) BETWEEN DATE_SUB(NOW(), INTERVAL 1 MONTH) AND NOW()
) sub1
LEFT OUTER JOIN ORDERS
ON sub1.sdate = DATE_FORMAT(ORDERS.date, "%M %e")
GROUP BY sub1.sdate

这可处理长达 1000 天的日期范围。

请注意，根据您用于日期的字段类型，可以轻松提高效率。

编辑 - 根据要求，获取每月订单数:-

SELECT aMonth, COUNT(ORDERS.id) as Norders
FROM
(
    SELECT DATE_FORMAT(DATE_SUB(NOW(), INTERVAL months.i MONTH), "%Y%m") as sdate, DATE_FORMAT(DATE_SUB(NOW(), INTERVAL months.i MONTH), "%M") as aMonth 
    FROM (SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10 UNION SELECT 11)months
    WHERE DATE_SUB(NOW(), INTERVAL months.i MONTH) BETWEEN DATE_SUB(NOW(), INTERVAL 12 MONTH) AND NOW()
) sub1
LEFT OUTER JOIN ORDERS
ON sub1.sdate = DATE_FORMAT(ORDERS.date, "%Y%m")
GROUP BY aMonth