MERGE DELETE 仅基于父 id

Question

我有一个名为“可用性”的表，看起来像这样。

| Id | Allocated | AverageCost | Demand | InStock | SourceDate | LocationId | ItemId

现在 ItemId 是与 Items 表的关系，而 LocationId 是与 Location 表的关系，每个项目的每个位置只能有 1 条记录。

我有另一个表正在更新可用性，但仅适用于某些项目，而不是所有项目，现在我想进行合并并插入目标中缺少的所有内容，并更新目标，但我的挑战是什么当假设某些特定项目的位置已被删除时，我会做什么，当源缺少我现在匹配的项目的可用性时，我想删除，

这是一个例子。假设在源中我有多个 ItemId 2356 的记录，现在我只想将它们与 target 匹配 itemId = 2356 的记录。所以当我在 ItemId 2356 的目标中有 6 条记录时，在源中我只有 4 条记录对于这个 ItemId，我希望它应该从目标中删除源中缺少的 2 条记录。

目标

ID  A   AC     D   IS    Date      LocationId    ItemID
1 | 0 | 2.36 | 23 | 56 | 3/23/18 | 5689       | 2356 
2 | 0 | 5.36 | 10 | 34 | 3/23/18 | 5634       | 2356 
3 | 0 | 5.36 | 10 | 34 | 3/23/18 | 5756       | 1497
4 | 0 | 5.36 | 10 | 34 | 3/23/18 | 5371       | 2356 
5 | 0 | 5.36 | 10 | 34 | 3/23/18 | 2873       | 2356
6 | 0 | 5.36 | 10 | 34 | 3/23/18 | 8549       | 2356
7 | 0 | 5.36 | 10 | 34 | 3/23/18 | 8549       | 3585
8 | 0 | 5.36 | 10 | 34 | 3/23/18 | 8549       | 2943
9 | 0 | 5.36 | 10 | 34 | 3/23/18 | 2958       | 2356

来源

 A   AC     D   IS    Date      LocationId    ItemID
 0 | 2.36 | 23 | 56 | 3/23/18 | 5689       | 2356 
 0 | 5.36 | 10 | 34 | 3/23/18 | 5634       | 2356 
 0 | 5.36 | 10 | 34 | 3/23/18 | 2873       | 2356
 0 | 5.36 | 10 | 34 | 3/23/18 | 8549       | 2356

但不幸的是，我当前的 MERGE 正在从目标中删除它在源中找不到的所有内容，包括具有不同 ItemId 的记录。

这是我的 MERGE。

MERGE Availability AS target
USING #tmpAvailability AS SOURCE 
ON target.[locationId] = SOURCE.[locationId]
  AND target.[ItemId] = Source.[ItemId]   


WHEN MATCHED THEN 

UPDATE SET TARGET.[Allocated] = source.[Allocated],  
           TARGET.[AverageCost] =  source.[AverageCost],
           TARGET.[Demand] =  source.[Demand],
           TARGET.[InStock] =  source.[InStock],
           TARGET.[SourceDate] =  source.[SourceDate]


WHEN NOT MATCHED BY TARGET THEN  

INSERT ([Allocated],[AverageCost],[Demand],[InStock],[SourceDate],[LocationId],[ItemId])          
VALUES (SOURCE.[Allocated] ,SOURCE.[AverageCost],source.[Demand],source.[InStock],source.[SourceDate],source.[LocationId],source.[ItemId])


when Not Matched By Source and source.[ItemId] is not null then
DELETE; 

Answer 1

请试试这个：

;WITH MergeTable AS (
    SELECT a.[Allocated],a.[AverageCost],a.[Demand],a.[InStock],a.[SourceDate],a.[LocationId],a.[ItemId]
    FROM Availability a
    WHERE a.ItemID IN (SELECT DISTINCT ItemID FROM #tmpAvailability)
)
MERGE MergeTable AS target
USING #tmpAvailability AS SOURCE 
    ON target.[locationId] = SOURCE.[locationId]
        AND target.[ItemId] = Source.[ItemId]   
WHEN MATCHED THEN 
UPDATE SET TARGET.[Allocated] = source.[Allocated],  
           TARGET.[AverageCost] =  source.[AverageCost],
           TARGET.[Demand] =  source.[Demand],
           TARGET.[InStock] =  source.[InStock],
           TARGET.[SourceDate] =  source.[SourceDate]

WHEN NOT MATCHED BY TARGET THEN  
INSERT ([Allocated],[AverageCost],[Demand],[InStock],[SourceDate],[LocationId],[ItemId])          
VALUES (SOURCE.[Allocated] ,SOURCE.[AverageCost],source.[Demand],source.[InStock],source.[SourceDate],source.[LocationId],source.[ItemId])

WHEN NOT MATCHED BY SOURCE AND source.[ItemId] IS NOT NULL THEN
DELETE;