Joachim Zobel schrob: > Am Samstag, den 04.06.2005, 15:22 -0500 schrieb Bruno Wolff III: >> On Sat, Jun 04, 2005 at 21:53:24 +0200, >> Joachim Zobel <jzobel@xxxxxxxxxxxxxxx> wrote: >> > So WITH will allow recursion so I can walk the graph, right? Does this >> > mean I can recursively join until a terminating condition is reached? >> >> It can be used to compute transitive closures, which I think is what >> you are really looking for. > > There aren't any plans to implement grouping by a user defined > equivalence relation? This is the other thing I am missing. But OK, WITH Isn't this already possible by representing the relation through its canonical mapping (i.e. f(a)=f(b) <=> a relates to b)? You could then use GROUP BY f(x) to group data into its equivalence classes. regards, Andreas ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly