Hello Dave J. You are right. I used explain analyse and the last operation was unique and that means remove all duplicates and I select distinct * from view1 and I get 233.
Regards ________________________________ From: David Johnston <pol...@yahoo.com> To: 'salah jubeh' <s_ju...@yahoo.com>; 'pgsql' <pgsql-general@postgresql.org> Sent: Wednesday, March 21, 2012 4:31 PM Subject: Re: [GENERAL] strange result with union Thus view1 must be returning 3 pairs of duplicate rows which are then being combined into 3 individual rows during the de-duplication pass. Dave J. From:pgsql-general-ow...@postgresql.org [mailto:pgsql-general-ow...@postgresql.org] On Behalf Of salah jubeh Sent: Wednesday, March 21, 2012 11:26 AM To: pgsql Subject: [GENERAL] strange result with union Hello, Today, I have encounterd a strange result and I want to trace it but I do not know how. I have two views having union as in q3. q1 returns 236 rows, q2 returns 0 rows. I expected q3 to return 236 rows but I get 233 ... q1: select * FROM view1 -- reurns 236 rows q2: select * FROM view2 -- returns 0 rows q3: select * FROM view1 union select * FROM view2 --returns 233 rows q4: select * FROM view1 union all select * FROM view2 --returns 236 rows I knwo that the union operator filter out duplicate rows but the intresting part is that view2 returns 0 rows. If I use UNION all I get the expected result which is 236 rows. I am almost sure that view1 defenesion is dependent of view2 defnesion. for example I can drop view2 without droping view1. and I can drop view1 without dropping view2. I am running on version "PostgreSQL 8.3.12 on x86_64-pc-linux-gnu, compiled by GCC gcc-4.3.real (Debian 4.3.2-1.1) 4.3.2" Regards
