Can MERGE also DELETE? Example only shows INSERT / UPDATE - database

Question

I was reading the MSDN site here:
http://technet.microsoft.com/en-us/library/bb510625.aspx
and I'm a little confused about one thing.
The example from the site (copied at the bottom) uses the line WHEN NOT MATCHED BY TARGET. My question is, can I use that to do inserts, updates, and deletes all in the same merge? For example:
--Lazy syntax, but I think you get the idea.
MERGE x AS TARGET USING (ID, [More Fields...]) AS SOURCE
WHEN MATCHED
update
WHEN NOT MATCHED IN TARGET
insert
WHEN NOT MATCHED IN SOURCE
delete
MSDN EXAMPLE:
USE AdventureWorks2012;
GO
-- Create a temporary table variable to hold the output actions.
DECLARE #SummaryOfChanges TABLE(Change VARCHAR(20));
MERGE INTO Sales.SalesReason AS Target
USING (VALUES ('Recommendation','Other'), ('Review', 'Marketing'),
('Internet', 'Promotion'))
AS Source (NewName, NewReasonType)
ON Target.Name = Source.NewName
WHEN MATCHED THEN
UPDATE SET ReasonType = Source.NewReasonType
WHEN NOT MATCHED BY TARGET THEN
INSERT (Name, ReasonType) VALUES (NewName, NewReasonType)
OUTPUT $action INTO #SummaryOfChanges;
-- Query the results of the table variable.
SELECT Change, COUNT(*) AS CountPerChange
FROM #SummaryOfChanges
GROUP BY Change;

Answer 1

If you're doing a wholesale swap of the table, then one way would be to create two additional schemas:
CREATE SCHEMA shadow AUTHORIZATION dbo;
CREATE SCHEMA cache AUTHORIZATION dbo;
Now create a copy of your table in the cache schema:
CREATE TABLE cache.SalesReason(Name ...);
Now when you are doing your switch operation:
TRUNCATE TABLE cache.SalesReason;
INSERT cache.SalesReason(Name ...) SELECT ... FROM source;
-- this is a metadata operation so extremely fast - it will wait
-- for existing locks to be released, but won't block new locks
-- for very long at all:
BEGIN TRANSACTION;
ALTER SCHEMA shadow TRANSFER Sales.SalesReason;
ALTER SCHEMA Sales TRANSFER cache.SalesReason;
COMMIT TRANSACTION;
ALTER SCHEMA cache TRANSFER shadow.SalesReason;
TRUNCATE TABLE cache.SalesReason;
-- truncate is optional - I usually kept the data around for debugging
This won't work if you have foreign keys and other dependencies, and of course it completely invalidates statistics etc. and this, in turn, can affect plans, but if the most important thing is getting accurate data in front of your users with minimal interruption, this can be an approach to consider.