带有日期条件和 GROUP BY 的 Dsum

Question

我想编写一个访问查询（我认为 SQL 最合适），以便为每个产品检索单个数字或数字总和（如果这些数字绑定到相似日期）。

我的表格如下所示：

Tck1    DeD1    Bdf1
Tck1    DeD2    Bdf2
Tck1    DeD3    Bdf3
Tck2    DeD1    Bdf1
Tck2    DeD1    Bdf2
Tck2    DeD1    Bdf3
Tck2    DeD2    Bdf4
Tck3    DeD1    Bdf1
Tck3    DeD2    Bdf2

如您所见，对于 Tck1 和 Tck2，我只需要检索 Bdf1，但对于 Tck2，我需要对 Bdf1、Bdf2 和 Bdf3 求和

我尝试过（不成功）一些说法：

SELECT Sum([tblB].Bdf) As SumOfBdf
FROM [tblB]
GROUP BY Tck
HAVING (DeD = Min(Ded));

还有：

SELECT Sum([tblB].Bdf) As Expr1
FROM [tblB]
GROUP BY Tck
HAVING (DeD = Min(Ded));

知道我应该改变什么来提取数据吗？谢谢

感谢所有看过它的人，尤其是 Gord。

以下是一句话的答案：

SELECT tblB.Tck, tblB.DeD, Sum(tblB.Bdf) AS SumOfBdf
FROM tblB
GROUP BY tblB.Tck, tblB.DeD
HAVING (((tblB.DeD) In (SELECT Min(tblB.DeD) AS MinOfDeD FROM tblB GROUP BY tblB.Tck;)));

Answer 1

假设您的数据如下所示：

ID  Tck   DeD         Bdf
--  ----  ----------  ---
 1  Tck1  2013-01-01  100
 2  Tck1  2013-01-02  101
 3  Tck1  2013-01-03  102
 4  Tck2  2013-02-01  201
 5  Tck2  2013-02-01  202
 6  Tck2  2013-02-01  203
 7  Tck2  2013-02-02  204
 8  Tck3  2013-03-01  301
 9  Tck3  2013-03-02  302

那么返回每个 [Tck] 最早日期的查询将是

SELECT Tck, Min(DeD) AS MinOfDeD FROM tblB GROUP BY Tck

这给了我们

Tck   MinOfDeD  
----  ----------
Tck1  2013-01-01
Tck2  2013-02-01
Tck3  2013-03-01

下一步是使用该查询作为子查询来隔离属于这些日期的行

SELECT tblB.Tck, tblB.DeD, tblB.Bdf
FROM
    tblB
    INNER JOIN
    (
        SELECT Tck, Min(DeD) AS MinOfDeD FROM tblB GROUP BY Tck
    ) AS minDates
        ON tblB.Tck = minDates.Tck AND tblB.DeD = minDates.MinOfDeD

返回

Tck   DeD         Bdf
----  ----------  ---
Tck1  2013-01-01  100
Tck2  2013-02-01  201
Tck2  2013-02-01  202
Tck2  2013-02-01  203
Tck3  2013-03-01  301

最后，我们可以将其包装在一个聚合查询中，以提供总和

SELECT Tck, DeD, Sum(Bdf) AS SumOfBdf
FROM
    (
        SELECT tblB.Tck, tblB.DeD, tblB.Bdf
        FROM
            tblB
            INNER JOIN
            (
                SELECT Tck, Min(DeD) AS MinOfDeD FROM tblB GROUP BY Tck
            ) AS minDates
                ON tblB.Tck = minDates.Tck AND tblB.DeD = minDates.MinOfDeD
    )
GROUP BY Tck, DeD

返回

Tck   DeD         SumOfBdf
----  ----------  --------
Tck1  2013-01-01       100
Tck2  2013-02-01       606
Tck3  2013-03-01       301

编辑回复：评论

如果我们稍微调整一下测试数据：

ID  Tck   DeD         Bdf
--  ----  ----------  ---
 1  Tck1  2013-01-01  100
 2  Tck1  2013-01-02  101
 3  Tck1  2013-01-03  102
 4  Tck2  2013-01-02  201

然后是您评论中的查询（和更新的问题）

SELECT tblB.Tck, tblB.DeD, Sum(tblB.Bdf) AS SumOfBdf 
FROM tblB 
GROUP BY tblB.Tck, tblB.DeD 
HAVING (((tblB.DeD) In (SELECT Min(tblB.DeD) AS MinOfDeD FROM tblB GROUP BY tblB.Tck;)));

为“Tck1”返回两行

Tck   DeD         SumOfBdf
----  ----------  --------
Tck1  2013-01-01       100
Tck1  2013-01-02       101
Tck2  2013-01-02       201

因为 HAVING 子句不区分 [Tck] 的 Min(dates)

我在此编辑上方的答案中的最后一个查询（确实在“一个查询”中提供了解决方案，尽管它使用了几个子查询），返回

Tck   DeD         SumOfBdf
----  ----------  --------
Tck1  2013-01-01       100
Tck2  2013-01-02       201