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