MERGE statement to update temporal table (SCD 2)

Transact-SQL
,
3

Here's a full example:

DECLARE @InsertedOrders AS TABLE
(
  orderid   INT  NOT NULL PRIMARY KEY,
  custid    INT  NOT NULL,
  empid     INT  NOT NULL,
  orderdate DATE NOT NULL
);

INSERT INTO @InsertedOrders(orderid, custid, empid, orderdate)
  SELECT orderid, custid, empid, orderdate
  FROM (MERGE INTO Sales.MyOrders AS TGT
        USING (VALUES(1,        70,      1,      '20061218'),
                     (2,        70,      7,      '20070429'),
                     (3,        70,      7,      '20070820'),
                     (4,        70,      3,      '20080114'),
                     (5,        70,      1,      '20080226'),
                     (6,        70,      2,      '20080410'))
               AS SRC(orderid,  custid,  empid,  orderdate )
          ON SRC.orderid= TGT.orderid
        WHEN MATCHED AND (   TGT.custid    <> SRC.custid
                          OR TGT.empid     <> SRC.empid
                          OR TGT.orderdate <> SRC.orderdate) THEN UPDATE
          SET TGT.custid    = SRC.custid,
              TGT.empid     = SRC.empid,
              TGT.orderdate = SRC.orderdate
        WHEN NOT MATCHED THEN INSERT
          VALUES(SRC.orderid, SRC.custid, SRC.empid, SRC.orderdate)
        WHEN NOT MATCHED BY SOURCE THEN
          DELETE
        OUTPUT
          $action AS the_action, inserted.*) AS D
  WHERE the_action = 'INSERT';

SELECT *
FROM @InsertedOrders;