SQL Server 2008新特性 Merge 详细见联机手册

USE AdventureWorks2008R2;
GO
CREATE PROCEDURE dbo.InsertUnitMeasure
@UnitMeasureCode nchar ( 3 ),
@Name nvarchar ( 25 )
AS
BEGIN
SET NOCOUNT ON ;
-- Update the row if it exists.
UPDATE Production.UnitMeasure
SET Name = @Name
WHERE UnitMeasureCode = @UnitMeasureCode
-- Insert the row if the UPDATE statement failed.
IF ( @@ROWCOUNT = 0 )
BEGIN
INSERT INTO Production.UnitMeasure (UnitMeasureCode, Name)
VALUES ( @UnitMeasureCode , @Name )
END
END ;
GO
-- Test the procedure and return the results.
EXEC InsertUnitMeasure @UnitMeasureCode = ' ABC ' , @Name = ' Test Value ' ;
SELECT UnitMeasureCode, Name FROM Production.UnitMeasure
WHERE UnitMeasureCode = ' ABC ' ;
GO

-- Rewrite the procedure to perform the same operations using the MERGE statement.
-- Create a temporary table to hold the updated or inserted values from the OUTPUT clause.
CREATE TABLE #MyTempTable
(ExistingCode nchar ( 3 ),
ExistingName nvarchar ( 50 ),
ExistingDate datetime ,
ActionTaken nvarchar ( 10 ),
NewCode nchar ( 3 ),
NewName nvarchar ( 50 ),
NewDate datetime
);
GO
ALTER PROCEDURE dbo.InsertUnitMeasure
@UnitMeasureCode nchar ( 3 ),
@Name nvarchar ( 25 )
AS
BEGIN
SET NOCOUNT ON ;

MERGE Production.UnitMeasure AS target
USING ( SELECT @UnitMeasureCode , @Name ) AS source (UnitMeasureCode, Name)
ON (target.UnitMeasureCode = source.UnitMeasureCode)
WHEN MATCHED THEN
UPDATE SET Name = source.Name
WHEN NOT MATCHED THEN
INSERT (UnitMeasureCode, Name)
VALUES (source.UnitMeasureCode, source.Name)
OUTPUT deleted. * , $action, inserted. * INTO #MyTempTable;
END ;
GO
-- Test the procedure and return the results.
EXEC InsertUnitMeasure @UnitMeasureCode = ' ABC ' , @Name = ' New Test Value ' ;
EXEC InsertUnitMeasure @UnitMeasureCode = ' XYZ ' , @Name = ' Test Value ' ;
EXEC InsertUnitMeasure @UnitMeasureCode = ' ABC ' , @Name = ' Another Test Value ' ;

SELECT * FROM #MyTempTable;
-- Cleanup
DELETE FROM Production.UnitMeasure WHERE UnitMeasureCode IN ( ' ABC ' , ' XYZ ' );
DROP TABLE #MyTempTable;
GO