Execute the following SQL Server T-SQL script in SSMS Query Editor to demonstrate how to update the product names in the Product table from a different database using 3-part naming (referencing):

USE tempdb;

-- Create test table with SELECT INTO  

SELECT * INTO Product

FROM AdventureWorks.Production.Product

-- Blank out product name

UPDATE Product SET Name=''

SELECT * FROM Product

-- Update product name

-- by using 3-part reference to access other database table

UPDATE P SET P.[Name]=AWP.[Name]

FROM Product P

JOIN AdventureWorks.Production.Product AWP

ON AWP.ProductID=P.ProductID;

SELECT * FROM Product

USE tempdb;

DROP TABLE Product

GO

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Related articles:

Mastering the SQL UPDATE Syntax

UPDATE - SQL Server 2000 - Changes existing data in a table.