>By the way, your syntax "insert into @t select 1 union select null union select 2" I have never seen before. It is very interesting. I am going to study it to figure out what are you doing here <g>.

It's common syntax for SQL Server, but I don't know if it works in other databases. In SQL Server 2008 you can use even easier version like

insert into @t values (1), (Null), (3)

Also in SQL Server 2008 you can use shortcuts like

declare @Param = null

or

set i=++ -- the later version I personally never use, I always use the full syntax