Re: Retrieval of duplicates, possible??
From: Philip Lijnzaad <lijnzaad_at_ebi.ac.uk>
Date: 2000/05/25
Message-ID: <u7ln0yznal.fsf_at_o2-3.ebi.ac.uk>#1/1
Date: 2000/05/25
Message-ID: <u7ln0yznal.fsf_at_o2-3.ebi.ac.uk>#1/1
Mark> I think this is a good solution and would probably work as well or Mark> better than what I want to mention. The original post mentioned union Mark> and minus. Isn't it asking for what the third set operator is designed Mark> to do, namely, intersect, which shows members common to both sets.
First of all, it wasn't at all clear why there was any need for the comparison between the two tables, Policy and Commission_Policy. If there was, it should have been described better.
Secondly, INTERSECT is also a set operator, and as such doesn't yield _any_ duplicates. So {a, a, b, c} INTERSECT { a, e, f} simply gives { a } (_not_ { a, a }) and {a, a, b, c} INTERSECT { b,e , f} simply gives { b }. So there is nothing that can help you find duplicates. You simply cannot use _any_ set operator to find duplicates. Cheers,
Philip
-- /dev/brain: character special (53/0) ----------------------------------------------------------------------------- Philip Lijnzaad, lijnzaad_at_ebi.ac.uk \ European Bioinformatics Institute,rm A2-24Received on Thu May 25 2000 - 00:00:00 CEST
+44 (0)1223 49 4639 / Wellcome Trust Genome Campus, Hinxton
+44 (0)1223 49 4468 (fax) \ Cambridgeshire CB10 1SD, GREAT BRITAIN
PGP fingerprint: E1 03 BF 80 94 61 B6 FC 50 3D 1F 64 40 75 FB 53