MERGE Statement in MS SQL Server 2008

MS SQL Server 2008 introduces new MERGE statement. You can perform INSERT, UPDATE, and DELETE operations in a single statement using MERGE. The MERGE syntax allows you to join a data source with a target table or view, and then perform multiple actions based on the results of that join.
You can read about new MERGE statement at MSDN Site.
Here are examples of MERGE from MSDN:

MERGE Production.ProductInventory AS pi
USING (SELECT ProductID, SUM(OrderQty) FROM Sales.SalesOrderDetail sod
JOIN Sales.SalesOrderHeader soh
ON sod.SalesOrderID = soh.SalesOrderID
AND soh.OrderDate = GETDATE()
GROUP BY ProductID) AS src (ProductID, OrderQty)
ON (pi.ProductID = src.ProductID)
WHEN MATCHED AND pi.Quantity - src.OrderQty = 0
THEN DELETE
WHEN MATCHED
THEN UPDATE SET pi.Quantity = pi.Quantity - src.OrderQty;

MERGE Departments AS d
USING Departments_delta AS dd
ON (d.DeptID = dd.DeptID)
WHEN MATCHED AND d.Manager <> dd.Manager OR d.DeptName <> dd.DeptName
THEN UPDATE SET d.Manager = dd.Manager, d.DeptName = dd.DeptName
WHEN NOT MATCHED THEN
INSERT (DeptID, DeptName, Manager)
VALUES (dd.DeptID, dd.DeptName, dd.Manager)
WHEN SOURCE NOT MATCHED THEN
DELETE;