How do I identify a blank uniqueidentifier in SQL Server 2005?

Question

I'm getting a uniqueidentifier into a Stored Procedure that looks like this

00000000-0000-0000-0000-000000000000.

This seems like a simple thing, but how can identify that this is a blank uniqueidentifier?

If I get a value like this DDB72E0C-FC43-4C34-A924-741445153021 I want to do X

If I get a value like this 00000000-0000-0000-0000-000000000000 I do Y

Is there a more elegant way then counting up the zeros?

Thanks in advance

Answer 1

compare to

cast(cast(0 as binary) as uniqueidentifier)

?