MERGE Statement in Microsoft SQL Server 2008

Merge statement allows a single statement for INSERT, DELETE and UPDATE a row that depends on a condition. The target table for certain operations is based on the results of join with a source table. 

For example

MERGE InventoryMaster AS invmstr
USING (SELECT InventoryID, Descr FROM NewInventory) AS src
ON invmstr. InventoryID = src. InventoryID
WHEN MATCHED THEN
          UPDATE SET invmstr.Descr = src.Descr
WHEN NOT MATCHED THEN

INSERT (InventoryID, Descr) VALUES (src. InventoryID, src.Descr);

See Also