SQL Server Merge - Getting matched records to another temp table

Question

I have a MERGE query to update data. In case of no match I am inserting records to source getting the output to a temporary table.

Would it be possible to get the matched records to temporary table as well? Basically to avoid duplication of data in further processing I need to have copy of matched records.

This is my MERGE command:

MERGE Product.ProductHeaderRepository AS t 
USING (SELECT GETDATE() as d, c1, c2, c3,
Name FROM Supplier.ProductHeaderImport
WHERE (BatchID = @BatchID) ) AS s
ON dbo.GetProductHeaderId(s.c1,S.c2,S.c3) <0
WHEN NOT MATCHED BY TARGET THEN
  INSERT (Name, c1,c2,c3) VALUES (Name, c2,c2,c3)
OUTPUT INSERTED.iD, s.c1, s.c2, s.c3 INTO @TmpTable;

Solution

You could create a MATCHED clause that does not change anything and just updates a variable, e.g.

DECLARE @T1 TABLE (A INT, B INT);
DECLARE @T2 TABLE (A INT, B INT);
DECLARE @T3 TABLE (Action VARCHAR(20), A INT, B INT);

INSERT @T1 VALUES (1, 1), (2, 2), (3, 3);
INSERT @T2 VALUES (1, 0), (2, NULL), (4, 0);

DECLARE @I INT; -- VARIABLE TO UPDATE

MERGE @T2 B
USING @T1 A
    ON A.A = B.A
WHEN MATCHED THEN 
    UPDATE SET @I = 1   -- DO NOTHING MEANINGFUL IN THE UPDATE;
WHEN NOT MATCHED BY TARGET THEN 
    INSERT (A, B) VALUES (A.A, A.B)
OUTPUT $action, ISNULL(inserted.A, deleted.A), ISNULL(inserted.B, deleted.B) INTO @T3;

SELECT  *
FROM    @T3;

Will return:

Action  A   B
INSERT  3   3
UPDATE  1   0
UPDATE  2   NULL

So if you add a new column to @TmpTable to store the action you can get your matched rows using:

SELECT  *
FROM    @TmpTable
WHERE   Action = 'UPDATE';

And your new rows using:

SELECT  *
FROM    @TmpTable
WHERE   Action = 'INSERT';