當同一表的其他列的多個記錄匹配時，更新列

Question

我有如下表：

            Input table:
            RequestNumber            TrackName         Date
            -----------------------------------------------------------
            02209                    Middle         2017-05-28 00:00:00
            0263                     Middle         2017-06-29 00:00:00
            0633                     Middle         2017-09-10 00:00:00
            0762                     Back           2017-06-23 00:00:00
            0762                     Front          2017-06-23 00:00:00
            0762                     Middle         2017-06-23 00:00:00
            01839                    Middle         2017-03-09 00:00:00

我需要檢查“ TrackName”的“ RequestNumber”和“ Date”是否相同。 如果“ requestNumber”和“ Date”的多個記錄匹配，則應將“ TrackName”列更新為“所有三個”，如下面的輸出示例所示（在此示例中，有3條記錄匹配）

            Output table:
            RequestNumber            TrackName         Date
            -----------------------------------------------------------
            02209                    Middle         2017-05-28 00:00:00
            0263                     Middle         2017-06-29 00:00:00
            0633                     Middle         2017-09-10 00:00:00
            0762                     All three      2017-06-23 00:00:00
            01839                    Middle         2017-03-09 00:00:00

為了獲得上面指定的輸出，這是我嘗試過的SQL。 Howveer，將所有TrackName更新為所有三個。

            UPDATE a 
            SET a.[TrackName] = 'All three'
            FROM Table1 as a
            INNER JOIN 
            (SELECT [RequestNumber], row_number() OVER (ORDER BY [RequestNumber] DESC) as rowNumber
            FROM Table1 ) drRowNumbers ON drRowNumbers.[RequestNumber] = a.[RequestNumber] and drRowNumbers.[Date] = a.[Date]

希望我已經正確解釋了這一點。 我在做什么？ 任何查詢來解決這個問題？

注意：記錄是動態發送的，因此無法進行硬編碼（如果有）。

謝謝。

Answer 1

嘗試這個。 這將返回“全部3”，而不是“全部3”-

SELECT RequestNumber,
CASE 
    WHEN COUNT(*) = 1 THEN MAX(TrackName) 
    ELSE 'All ' + CAST( COUNT(*) AS VARCHAR) 
END TrackName,
Date
FROM your_table
GROUP BY RequestNumber,Date

Answer 2

我認為您想要SELECT語句：

SELECT t1.RequestNumber, (CASE WHEN COUNT(DISTINCT t1.TrackName) = t2.TrackNo 
                               THEN CONCAT('All ', t2.TrackNo)  
                               ELSE MIN(t1.TrackName) 
                          END) AS TrackName, t1.Date
FROM table1 t1 CROSS JOIN
     (SELECT COUNT(DISTINCT TrackName) AS TrackNo FROM table1) AS t2
GROUP BY t1.RequestNumber, t1.Date;

Answer 3

這不僅是更新，還是刪除。
這意味着您必須執行兩個步驟，一個步驟是更新相關記錄，另一個步驟是刪除第一步創建的重復項。

當兩個步驟都在事務中row_number() over()可以使用幾個使用窗口函數的常用表表達式來完成此操作，例如count() over()和row_number() over() 。

首先，創建並填充示例表（ 請在以后的問題中保存此步驟）：

DECLARE @T AS TABLE
(
    RequestNumber int,
    TrackName varchar(10),
    [Date] datetime2
);

INSERT INTO @T (RequestNumber, TrackName, Date) VALUES
(02209, 'Middle', '2017-05-28 00:00:00'),
(0263, 'Middle', '2017-06-29 00:00:00'),
(0633, 'Middle', '2017-09-10 00:00:00'),
(0762, 'Back', '2017-06-23 00:00:00'),
(0762, 'Front', '2017-06-23 00:00:00'),
(0762, 'Middle', '2017-06-23 00:00:00'),
(01839, 'Middle', '2017-03-09 00:00:00');

接下來，啟動一個try塊和一個事務：

BEGIN TRY
BEGIN TRANSACTION;

然后，識別並更新相關記錄：

WITH CTE AS
(
    SELECT  RequestNumber, 
            TrackName, 
            Date,
            COUNT(TrackName) OVER(PARTITION BY RequestNumber, Date) As Cnt
    FROM @T
)

UPDATE CTE
SET TrackName = 'All Three'
WHERE Cnt = 3;

接下來，刪除重復項：

WITH CTE AS
(
    SELECT  RequestNumber, 
            TrackName, 
            Date,
            ROW_NUMBER() OVER(PARTITION BY RequestNumber, Date ORDER BY TrackName) As Rn
    FROM @T
)

DELETE 
FROM CTE 
WHERE Rn > 1;

提交事務並關閉try塊：

COMMIT TRANSACTION;
END TRY

使用catch塊回滾事務：

BEGIN CATCH
    IF @@TRANCOUNT > 0
        ROLLBACK TRANSACTION

    -- you might want to print the result of ERROR_MESSAGE() here...
END CATCH

最后，選擇以查看更改：

SELECT  RequestNumber, 
        TrackName, 
        Date
FROM @T

結果：

RequestNumber   TrackName   Date
2209            Middle      28.05.2017 00:00:00
263             Middle      29.06.2017 00:00:00
633             Middle      10.09.2017 00:00:00
762             All Three   23.06.2017 00:00:00
1839            Middle      09.03.2017 00:00:00

您可以在rextester上看到一個現場演示 （減去那里不允許的交易部分，以及沒有交易就沒有意義的try ... catch）

Answer 4

試試這個

步驟1將記錄之一設置為全部三個

update table1
set TrackName = 'All Three'
where requestnumber in (select requestnumber
from table1
group by requestnumber,[date]
having count(*) = 3)
and trackname = 'Front'

步驟2刪除不再需要的數據

delete table1
where requestnumber in (select requestnumber
from table1
group by requestnumber,[date]
having count(*) = 3)
and trackname <> 'All Three'