usa NEWID()
funzione per generarne uno:
CREATE TABLE myTable(GuidCol uniqueidentifier
,NumCol int)
INSERT INTO myTable Values(NEWID(), 4)
SELECT * FROM myTable
oppure puoi impostarlo come valore predefinito:
CREATE TABLE myTable(GuidCol uniqueidentifier DEFAULT NEWSEQUENTIALID()
,NumCol int)
INSERT INTO myTable (NumCol) Values(4)
SELECT * FROM myTable