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Thursday, January 13, 2011

Merge Statement SQL SERVER 2008

    Using Merge Statement we can apply Insert, Update and Delete in a single statement

Following is the example for Merge Statement

; MERGE INTO comments AS PC
USING ( select [CommentID] , [Value] , [Comments] , [CommentTypeId]
from @tCommentsValues) as p
on PC.CommentID = p.CommentiD
WHEN MATCHED THEN
UPDATE SET Comments = p.comments,
DateModified = getdate(),
ModifiedBy = @UserID
WHEN NOT MATCHED BY TARGET THEN
 INSERT(CommentId,Comments,DateCreated,DateModified,Active,Deleted,CommentTypeId)
 VALUES (p.CommentID ,p.Comments ,getdate(),@UserID,1,0,[CommentTypeId])

2 comments:

Shamas Saeed said...

This help me to create a procedure quickly.

great post

Shamas Saeed said...

msdn code for all available options of Merge statement.

USE AdventureWorks2012;
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