Yes because it wasn't also in Wolfgang's initially provided desired result set and is filtered out by WHERE alt_b IS NOT NULL. Anyway as I understood Wolfgang already succesfully solved his problem. Gints Plivna http://www.gplivna.eu 2008/10/31 Michael Moore <michaeljmoore@xxxxxxxxx>: > let me try again... > not sure if this matters, but there is no AS for period 1 in the result set > for Gint's first solution. > Mike -- //www.freelists.org/webpage/oracle-l