what is the use of the output $ action in a Merge statement in Sql server 2008?
Omniscient MSDN says
$ actionAvailable only to the MERGE operator. Specifies a column of type nvarchar (10) in the OUTPUT clause of the MERGE statement that returns one of three values for each row: "INSERT", "UPDATE", or "DELETE", according to the action that was performed on that row.
$ action
Available only to the MERGE operator. Specifies a column of type nvarchar (10) in the OUTPUT clause of the MERGE statement that returns one of three values for each row: "INSERT", "UPDATE", or "DELETE", according to the action that was performed on that row.