Not possible, at least as I understand a GUID.

GUIDs are themselves generated using a number of factors, one of which is the unique (MAC?) number of a network card and have some "guarantee" to be unique across time for some billions of years or so.

Maybe you can replace your existing primary key with the GUID? Much more overhead, but still at least 4 bytes less than carrying both.

cheers


>Our tables contain primary keys, such as any other table. However, some specific XML requirement we have to deliver consists of sending the client a GUID that could be later use to query one of our record. The client doesn't want to receive the primary key. They want a GUID. So, we create them a GUID. However, they expect to send that query as a record recognition back to us when required. So, the simplest approach would be to add a GUID ID field in our table. But, is that really necessary? Just because of that, I'll end up with two primary key fields, one a GUID just for that. Isn't there a way to have the GUID generated based on a primary key value and degenerate it, when such a request will be launched, in order to recognize our primary key value?