Question

我正在尝试运行一份报告，该报告会在过去3个月内每天给出“情节”销售情况，而且我很难让SUM（）正确累加。单个Transaction_ID可以跨越多个Plot记录。通过下面的查询，如果有2个具有相同Transaction_ID的图，则将它们一起添加，这不是我想要的。我需要它只在SUM（）中使用一次Transaction行。

SELECT 
    DATE_FORMAT(Transactions.CreateDate,'%m-%d') AS MonthAndDay, 
    DATE_FORMAT(Transactions.CreateDate,'%M, %D') AS Day, 
    SUM(Transactions.AmountTotal) AS DailySales 
FROM 
    Transactions, 
    Plots 
WHERE 
    Transactions.Transaction_ID = Plots.Transaction_ID AND 
    Transactions.CreateDate <= CURDATE() AND 
    Transactions.CreateDate >= DATE_SUB(CURDATE(),INTERVAL 3 MONTH) 
GROUP BY 
    MonthAndDay 
ORDER BY 
    MonthAndDay ASC

表结构如下：

+-----------------------------------+----------------------------------------------------------------------------------------------------+------+-----+---------------------+----------------+
| Field                             | Type                                                                                               | Null | Key | Default             | Extra          |
+-----------------------------------+----------------------------------------------------------------------------------------------------+------+-----+---------------------+----------------+
| Transaction_ID                    | int(11)                                                                                            | NO   | PRI | NULL                | auto_increment | 
| CreateDate                        | datetime                                                                                           | NO   |     | 0000-00-00 00:00:00 |                | 
| AmountTotal                       | decimal(10,2)                                                                                      | NO   |     | 0.00                |                | 
+-----------------------------------+----------------------------------------------------------------------------------------------------+------+-----+---------------------+----------------+

+------------------------+-------------+------+-----+---------------------+----------------+
| Field                  | Type        | Null | Key | Default             | Extra          |
+------------------------+-------------+------+-----+---------------------+----------------+
| Plot_ID                | int(11)     | NO   | PRI | NULL                | auto_increment | 
| Transaction_ID         | int(11)     | YES  | MUL | NULL                |                | 
| Plot                   | varchar(10) | NO   |     | 0                   |                | 
+------------------------+-------------+------+-----+---------------------+----------------+

Answer 1

以下解决方案有效，尽管有子查询：

SELECT
   DATE_FORMAT(Transactions.CreateDate,'%m-%d') AS MonthAndDay,
   DATE_FORMAT(Transactions.CreateDate,'%M, %D') AS Day,
   SUM(Transactions.AmountTotal) AS DailySales
FROM
   Transactions
WHERE
   Transactions.Transaction_ID IN (SELECT DISTINCT Transaction_ID FROM Plots) AND
   Transactions.CreateDate <= CURDATE() AND
   Transactions.CreateDate >= DATE_SUB(CURDATE(),INTERVAL 3 MONTH)
GROUP BY
   MonthAndDay
ORDER BY
   MonthAndDay ASC;

Answer 2

脱离我的头脑，我认为以下方法可行，但我没有测试过，所以可能是错的：

SELECT 
    DISTINCT Transactions.Transaction_ID,
    DATE_FORMAT(Transactions.CreateDate,'%m-%d') AS MonthAndDay, 
    DATE_FORMAT(Transactions.CreateDate,'%M, %D') AS Day, 
    SUM(Transactions.AmountTotal) AS DailySales 
FROM 
    Transactions, 
    Plots 
WHERE 
    Transactions.Transaction_ID = Plots.Transaction_ID AND 
    Transactions.CreateDate <= CURDATE() AND 
    Transactions.CreateDate >= DATE_SUB(CURDATE(),INTERVAL 3 MONTH) 
GROUP BY 
    MonthAndDay 
ORDER BY 
    MonthAndDay ASC

第二次去：

SELECT 
    DATE_FORMAT(Transactions.CreateDate,'%m-%d') AS MonthAndDay, 
    DATE_FORMAT(Transactions.CreateDate,'%M, %D') AS DAY, 
    SUM(Transactions.AmountTotal) AS DailySales,
    COUNT(Transactions.Transaction_ID) AS Tmp
FROM 
    Transactions, 
    Plots
WHERE 
    Transactions.Transaction_ID = Plots.Transaction_ID AND 
    Transactions.CreateDate <= CURDATE() AND 
    Transactions.CreateDate >= DATE_SUB(CURDATE(),INTERVAL 3 MONTH) 
GROUP BY 
    Plots.Plot_ID, MonthAndDay 
ORDER BY 
    MonthAndDay ASC

这在Plots表中产生了3行，有两行引用Transaction_ID 2，一行引用Transaction_ID 1

这导致出现三个绘图行，但总和值显示正确。

如何为SUM（）选择DISTINCT行？

2 个答案: