SQL Server MERGE without a source table

Question

I am learning how to use SQL Server MERGE statement from this page: 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.*;

However all the examples I can find (such as the one above) are using an actual table as Source. Is it possible to directly pass the data? I would rather not create a temporary table for that (if possible and recommended?) How would the query above be modified?

Thank you

Answer 1

You could do it like this:

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.*;