On Mon, Apr 21, 2008 at 03:48:23PM +0200, Thomas Kellerer wrote: > name, id, parent_id > ROOT, 1, NULL > CHILD1, 2, 1 > CHILD2, 3, 1 > > I would have expected the following result: > > ROOT, NULL > ROOT, CHILD1 > ROOT, CHILD2 > > but the row with (ROOT,NULL) is not returned.
why would you expect it? the columns are: parent and child (on your output). you dont have any row that has *parent_id = 1* and id = NULL. you can get this output though: NULL, ROOT ROOT, CHILD1 ROOT, CHILD2 with this query: select p.name as parent, c.name as child from category c left outer join category p on c.parent_id = p.id depesz -- quicksil1er: "postgres is excellent, but like any DB it requires a highly paid DBA. here's my CV!" :) http://www.depesz.com/ - blog dla ciebie (i moje CV) -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
