Question

我正在学习如何使用此页面中的SQL Server MERGE语句： https://technet.microsoft.com/en-us/library/bb522522(v=sql.105).aspx

MERGE dbo.FactBuyingHabits AS Target
USING (SELECT CustomerID, ProductID, PurchaseDate FROM dbo.Purchases) AS Source
    ON (Target.ProductID = Source.ProductID AND Target.CustomerID = Source.CustomerID)

WHEN MATCHED THEN
    UPDATE SET Target.LastPurchaseDate = Source.PurchaseDate

WHEN NOT MATCHED BY TARGET THEN
    INSERT (CustomerID, ProductID, LastPurchaseDate)
    VALUES (Source.CustomerID, Source.ProductID, Source.PurchaseDate)

OUTPUT $action, Inserted.*, Deleted.*;

然而，我能找到的所有例子（例如上面的例子）都使用实际的表作为Source。是否可以直接传递数据？我宁愿不为此创建一个临时表（如果可能并建议？）如何修改上述查询？

谢谢

Answer 1

请尝试以下格式：

MERGE TARGET_TABLE AS I
USING (VALUES ('VALUE1','VALUE2')) as s(COL1,COL2)
ON I.COL1 = s.COL1
WHEN MATCHED THEN

您也可以参考： "Merge" style operation with literal values?

Answer 2

你可以这样做：

Declare @customerID int = 1;
Declare @productID int = 1;
Declare @purchaseDate date = '1900-01-01';

MERGE dbo.FactBuyingHabits AS Target
USING (SELECT CustomerID = @customerID, 
    ProductID = @productID, 
    PurchaseDate = @purchaseDate) AS Source
  ON (Target.ProductID = Source.ProductID AND Target.CustomerID = Source.CustomerID)
  WHEN MATCHED THEN
    UPDATE SET Target.LastPurchaseDate = Source.PurchaseDate
  WHEN NOT MATCHED BY TARGET THEN
    INSERT (CustomerID, ProductID, LastPurchaseDate)
    VALUES (Source.CustomerID, Source.ProductID, Source.PurchaseDate)
OUTPUT $action, Inserted.*, Deleted.*;

Answer 3

我需要一个更简单的版本，并提出以下解决方案：

MERGE Target_Table
USING (VALUES (0)) as s(x)
ON last_run is not null
WHEN not matched then
insert (last_run) values(getdate())
when matched then
update set last_run=getDate();

没有源表的SQL Server MERGE

3 个答案: