Question

我有一个查询尝试编制费用和信用报告，按项目代码和结算周期分组。它从中提取的Charge表具有以下格式：

BillingPeriod|ItemCode|ItemName|Charge|IsAdjustment|AdjustmentDate|ReportTimestamp

我认为，我遇到了一些问题，我当前的查询处理得非常好。由于有些时候计费代码没有出现在收费表中，因为我们没有收费，但是我想要一个显示每个结算周期的统一表，所以我制作了一个充满计费周期和零的虚拟表，和Union一起使用Charges表的结果，如下：

SELECT BillingPeriod, SumOfCharge AS Total FROM (
        SELECT BillingPeriod, 0 AS SumOfCharge
        FROM Charges
        UNION
        SELECT BillingPeriod, SUM(Charge) AS SumOfCharge
        FROM Charges
        WHERE (ItemCode Between 1900 and 1995)
        GROUP BY BillingPeriod
);

所以最终发生的事情是这样的：例如，比如我在2011年1月和3月收取一笔费用，但没有别的。该表将返回如下输出：

BillingPeriod|Charge
1/1/2011     |100.00
1/1/2011     |0
2/1/2011     |0
3/1/2011     |0
3/1/2011     |-23.00
4/1/2011     |0
5/1/2011     |0
6/1/2011     |0
7/1/2011     |0

我要做的是摆脱那些0值的行，并选择要在报告中显示的正确行。唯一棘手的部分是值可能是正数，负数或零，所以只做MAX就行不通。我也试过FIRST（）或LAST（），（COALESCE（））不起作用，我正在访问）。任何帮助将不胜感激。

Answer 1

只需按SumOfCharge总结BillingPeriod字段和分组：

SELECT BillingPeriod, SUM(SumOfCharge) AS Total FROM (
    SELECT BillingPeriod, 0 AS SumOfCharge
    FROM Charges
    UNION
    SELECT BillingPeriod, SUM(Charge) AS SumOfCharge
    FROM Charges
    WHERE (ItemCode Between 1900 and 1995)
    GROUP BY BillingPeriod
) GROUP BY BillingPeriod;

Answer 2

怎么样：

SELECT P.BillingPeriod, 
ISNULL(C.SumOfCharge,0) AS SumOfCharge
FROM (
    SELECT Distinct BillingPeriod
    FROM Charges) AS P
LEFT JOIN 
    (SELECT BillingPeriod, SUM(Charge) AS SumOfCharge
    FROM Charges
    WHERE (ItemCode Between 1900 and 1995)
    GROUP BY BillingPeriod) as C
ON P.BillingPeriod = C.BillingPeriod
ORDER BY P.BillingPeriod

Answer 3

这样的事情会起作用吗？

SELECT C.BillingPeriod,
       ISNULL(C1.SumOfCharge, 0) AS Total
FROM Charges
LEFT OUTER JOIN (SELECT BillingPeriod, SUM(Charge) AS SumOfCharge
                 FROM Charges
                 WHERE (ItemCode Between 1900 and 1995)
                 GROUP BY BillingPeriod) C1 ON C.BillingPeriod = C1.BillingPeriod

根据值从结果集中选择特定记录

3 个答案: