Creates a new Guid.
Guid NEWGUID()
Guid NEWGUID(int value)
Guid NEWGUID(Guid? g, int value)
NEWGUID(12)
Returns '0000000c-0000-0000-0000-000000000000'.
or
NEWGUID(NEWGUID(), 12)
Returns a new guid such as '0000000c-741d-4dc4-a924-0bde522f7718'.