0

例如，这将返回 55 的 ORDER NUMBER 和 55 的 Calc_ORDER_NUMBER_LAG，Calc_Qty_Changed 列没有给我 2，即使它们相等......

USE MfgMetrics

SELECT 
    [ORDER NUMBER], 
    [Calc_ORDER_NUMBER_LAG] = LAG([ORDER NUMBER],1,0) 
                                 OVER (Order By [ORDER NUMBER],[FileDate]), 
                                 --Order Number and File Date 
    [Order_Quantity], 
    [Calc_Order_Quantity_LAG] = LAG([Order_Quantity],1,0) 
                                   OVER (Order By [ORDER NUMBER], [FileDate]),
    [Calc_Qty_Changed] = 
        (CASE 
            WHEN [ORDER NUMBER] = [Calc_ORDER_NUMBER_LAG] THEN 2
            WHEN [ORDER NUMBER] != [Calc_ORDER_NUMBER_LAG] AND 
                        [Order_Quantity] != [Calc_Order_Quantity_LAG] AND 
                        [ACTUAL START DATE] != 0 AND 
                        [FileDate] >= [ACTUAL START DATE] THEN 1
            ELSE 0
        END)
FROM 
    dbo.Table_II

为什么每次都跳到 ELSE 0，即使满足其他 CASE WHEN 条件？

4

2 回答 2

2

您应该在 CASE 语句中重新编写 LAG() 函数。

create table table_II([ORDER NUMBER] int, [Order_Quantity] int, [FileDate] date);
insert into table_II values
(1, 10, '20180101'),
(2, 20, '20180102'),
(2, 30, '20180103');
GO

3 行受影响

SELECT 
    [ORDER NUMBER], 
    [Calc_ORDER_NUMBER_LAG] = LAG([ORDER NUMBER]) OVER (Order By [ORDER NUMBER], [FileDate]), 
    [Order_Quantity], 
    [Calc_Order_Quantity_LAG] = LAG([Order_Quantity]) OVER (Order By [ORDER NUMBER], [FileDate]),
    [Calc_Qty_Changed] = 
        (CASE 
            WHEN [ORDER NUMBER] = LAG([ORDER NUMBER]) OVER (Order By [ORDER NUMBER], [FileDate]) 
                 THEN 2
            WHEN [ORDER NUMBER] != LAG([ORDER NUMBER]) OVER (Order By [ORDER NUMBER], [FileDate]) 
                 AND [Order_Quantity] != LAG([Order_Quantity]) OVER (Order By [ORDER NUMBER], [FileDate]) 
                 --AND [ACTUAL START DATE] != 0 
                 --AND [FileDate] >= [ACTUAL START DATE] 
                 THEN 1
            ELSE 0
        END)
FROM 
    dbo.Table_II
GO

订单号 | Calc_ORDER_NUMBER_LAG | 订单_数量 | Calc_Order_Quantity_LAG | Calc_Qty_Changed
------------: | --------------------: | -------------: | ----------------------: | ---------------：
           1 |                  空| 10 |                    空| 0
           2 | 1 | 20 | 10 | 1
           2 | 2 | 30 | 20 | 2

dbfiddle在这里

于 2018-03-01T19:55:47.720 回答
1

我猜，因为我不知道数据的样子，你应该这样做：

USE MfgMetrics 
SELECT [ORDER NUMBER],
[Calc_ORDER_NUMBER_LAG] = LAG([ORDER NUMBER],1,0) OVER (Order By [ORDER NUMBER],[FileDate]), --Order Number and File Date
[Order_Quantity],
[Calc_Order_Quantity_LAG] = LAG([Order_Quantity],1,0) OVER (Order By [ORDER NUMBER], [FileDate]),
[Calc_Qty_Changed] = (CASE 
    WHEN [ORDER NUMBER]=LAG([ORDER NUMBER],1,0) OVER (Order By [ORDER NUMBER],[FileDate]) THEN 2 
    WHEN [ORDER NUMBER]!=LAG([ORDER NUMBER],1,0) OVER (Order By [ORDER NUMBER],[FileDate]) 
        AND [Order_Quantity] != LAG([Order_Quantity],1,0) OVER (Order By [ORDER NUMBER], [FileDate]) AND [ACTUAL START DATE] != 0 AND [FileDate] >= [ACTUAL START DATE] 
    THEN 1 
    ELSE 0 END) 
FROM dbo.Table_II
于 2018-03-01T20:00:37.837 回答