I'm just discovering the power of window functions. Is there any mathematical formalism for them, similar to relational algebra? It would seem to me that window functions aren't expressable in pure relational algebra, but that a well defined extension to it would be possible to express them; at least for those of us so inclinded, being able to think in terms of an alegbra would make reasoning about them much more powerful. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
