如何在do列中按日期划分分組數據

Question

我有一個數據集，我想按一個客戶代碼分組，對於每個代碼，我希望對一個月的日期之間的交易總數求和，並使每個月成為一個單獨的列。 我可以使這種動態變化成為我的主要關注點，即構造初始選擇以按需要輸出數據。

我有的：

SELECT [cmasterno]
    ,CASE 
        WHEN Month([dtrs]) = 1
            AND Year([dtrs]) = YEAR(GETDATE())
            THEN SUM([nftrsamt])
        END AS 'Jan 2014'
    ,CASE 
        WHEN Month([dtrs]) = 2
            AND Year([dtrs]) = YEAR(GETDATE())
            THEN SUM([nftrsamt])
        END AS 'Feb 2014'
FROM [AccountMate].[dbo].[gltrsn]
WHERE csource LIKE 'AR'
    AND cacctid LIKE '%4220%'
GROUP BY cmasterno

數據樣本將是

cmasterno   dtrs    ntrsamt
CEN01-A    1/24/2014    -22.2
AUT129-A    2/24/2014   -0.84
CEN01-A    1/22/2014    -19.86
CEN01-A    2/22/2014    -13.2
AUT129-A    1/22/2014   -18.42
AUT129-A    1/22/2014   -1
AUT129-A    2/22/2014   -316.56
CEN01-A    2/21/2014    -2.04

Answer 1

使用條件SUM

SELECT [cmasterno],
       SUM (CASE 
               WHEN Month([dtrs]) = 1 AND Year([dtrs]) = YEAR(GETDATE())
                    THEN [nftrsamt]
               ELSE 0
            END
           ) AS 'Jan 2014',
       SUM (CASE 
               WHEN Month([dtrs]) = 2 AND Year([dtrs]) = YEAR(GETDATE())
                    THEN [nftrsamt]
               ELSE 0
            END
           ) AS 'Feb 2014'
FROM [AccountMate].[dbo].[gltrsn]
WHERE csource LIKE 'AR'
    AND cacctid LIKE '%4220%'
GROUP BY cmasterno

Answer 2

為了完整起見，您也可以使用聯接來完成此操作

SELECT [cmasterno], sum(jan.nftrsamt) as 'Jan 2014', sum(feb.nftrsamt) as 'Feb 2014'
FROM [AccountMate].[dbo].[gltrsn] b
LEFT JOIN [AccountMate].[dbo].[gltrsn] jan on b.cacctid = jan.cacctid and Month(jan.[dtrs]) = 1 AND Year(jan.[dtrs]) = YEAR(GETDATE())
LEFT JOIN [AccountMate].[dbo].[gltrsn] feb on b.cacctid = feb.cacctid and Month(feb.[dtrs]) = 2 AND Year(feb.[dtrs]) = YEAR(GETDATE())
WHERE csource LIKE 'AR' AND cacctid LIKE '%4220%'
GROUP BY cmasterno

根據您的索引，聯接可能比情況快得多。 那是O（1）而不是O（N）