> Is there any way to implement a query in Postgres that would be in some way
> analogues to Oracle's START WITH/CONNECT BY structure?
Unfortunately, no such statements. Instead, you should write your own
functions which can operate on your own defined table. The table
represents the edges of the tree ("from" and "to"). You might have a look
on
ftp://pc10.radnoti-szeged.sulinet.hu/home/kovacsz/Linux/PostgreSQL/strukturak/
for some details about using partially ordered trees.
Regards, Zoltan