SQL Server Merge

This post showing you how to do an incremental update between 2 database tables. This post is using the famous Northwind database for SQL Server. I have a source table named Products1 as below.


To prepare for this demo. First, I have a table named Products2 with exactly the same structure as Products1. I then clear all the data in Products2.

TRUNCATE TABLE Products2

Insert all the rows from Products1 table to Products2 table. After this the data will be exactly the same.

INSERT INTO Products2 SELECT * FROM Products1

Update one record in Products1 table and insert a row into Products1 table.

UPDATE Products1 SET CategoryID = 2 WHERE ProductName =‘WebForm’

INSERt INTO Products1 (ProductName, Discontinued) VALUES (‘WinForm’,0)

You can try the MERGE command below then you will see the data in Products2 table will be exactly the same as Products1 table.

MERGE [dbo].[Products2] T USING (select * from [dbo].[Products1] with(nolock)) S

ON (T.ProductID = S.ProductID)WHEN MATCHED THEN 

UPDATE SET

    T.[ProductName] = S.[ProductName]

    ,T.[SupplierID] = S.[SupplierID]

    ,t.[CategoryID] = S.[CategoryID]

    ,T.[QuantityPerUnit] = S.[QuantityPerUnit]

    ,T.[UnitPrice] = S.[UnitPrice]

    ,T.[UnitsInStock] = S.[UnitsInStock]

    ,T.[UnitsOnOrder] = S.[UnitsOnOrder]

    ,T.[ReorderLevel] = S.[ReorderLevel]

    ,T.[Discontinued] = S.[Discontinued]

WHEN NOT MATCHED BY TARGET THEN
INSERT ([ProductID]
,

     [ProductName]

    ,[SupplierID]

    ,[CategoryID]

    ,[QuantityPerUnit]

    ,[UnitPrice]

    ,[UnitsInStock]

    ,[UnitsOnOrder]

    ,[ReorderLevel]

    ,[Discontinued])

        VALUES(S.[ProductID]    ,

     S.[ProductName]

    ,S.[SupplierID]

    ,S.[CategoryID]

    ,S.[QuantityPerUnit]

    ,S.[UnitPrice]

    ,S.[UnitsInStock]

    ,S.[UnitsOnOrder]

    ,S.[ReorderLevel]

    ,S.[Discontinued]);

About chanmingman

Since March 2011 Microsoft Live Spaces migrated to Wordpress (http://www.pcworld.com/article/206455/Microsoft_Live_Spaces_Moves_to_WordPress_An_FAQ.html) till now, I have is over 1 million viewers. This blog is about more than 50% telling you how to resolve error messages, especial for Microsoft products. The blog also has a lot of guidance teaching you how to get stated certain Microsoft technologies. The blog also uses as a help to keep my memory. The blog is never meant to give people consulting services or silver bullet solutions. It is a contribution to the community. Thanks for your support over the years. Ming Man is Microsoft MVP since year 2006. He is a software development manager for a multinational company. With 25 years of experience in the IT field, he has developed system using Clipper, COBOL, VB5, VB6, VB.NET, Java and C #. He has been using Visual Studio (.NET) since the Beta back in year 2000. He and the team have developed many projects using .NET platform such as SCM, and HR based applications. He is familiar with the N-Tier design of business application and is also an expert with database experience in MS SQL, Oracle and AS 400.
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