Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 064EA6353F2 for ; Thu, 27 Aug 2009 12:18:16 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 11950-10 for ; Thu, 27 Aug 2009 15:18:04 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 505026340DC for ; Thu, 27 Aug 2009 12:18:03 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id n7RFI2or003855; Thu, 27 Aug 2009 11:18:02 -0400 (EDT) To: rawi cc: pgsql-sql@postgresql.org Subject: Re: resolved: WITH RECURSIVE: ARRAY[id] All column datatypes must be hashable In-reply-to: <25168751.post@talk.nabble.com> References: <25167538.post@talk.nabble.com> <25168751.post@talk.nabble.com> Comments: In-reply-to rawi message dated "Thu, 27 Aug 2009 07:16:49 -0700" Date: Thu, 27 Aug 2009 11:18:02 -0400 Message-ID: <3854.1251386282@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.596 tagged_above=-10 required=5 tests=AWL=0.003, BAYES_00=-2.599 X-Spam-Level: X-Archive-Number: 200908/139 X-Sequence-Number: 33048 rawi writes: > The Error was caused because I used UNION in place of UNION ALL. > I still don't understand why the ARRAY (path) could not be grouped... Yeah, it's an unimplemented feature --- there's no hashing support for arrays. I hope to get that done for 8.5. In the meantime you have to use UNION ALL there. If you really need to eliminate duplicate rows, you can do that via DISTINCT in the outer query. regards, tom lane