Groups > comp.databases.postgresql > #353

Re: Joining two tables using two columns (instead of one)

From	Mladen Gogala <gogala.mladen@gmail.com>
Newsgroups	comp.databases.postgresql
Subject	Re: Joining two tables using two columns (instead of one)
Date	2012-04-11 03:21 +0000
Organization	solani.org
Message-ID	<pan.2012.04.11.03.21.12@gmail.com> (permalink)
References	<4f7d9c45$0$1745$426a34cc@news.free.fr> <4f7e91a4$0$16473$426a74cc@news.free.fr> <9u864cFf3tU1@mid.individual.net>

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On Fri, 06 Apr 2012 14:33:06 +0200, Robert Klemme wrote:

> SELECT subnet.id,val1.value,val2.value
>    FROM subnet JOIN probes AS val1 ON subnet.probe1 = val1.id JOIN
>    probes AS val2 ON subnet.probe2 = val2.id

If it was version 9.1, I would try with hash indexes on all involved 
columns. Hash algorithm is greatly improved in recent versions and it may 
provide the desired speed-up.

-- 
http://mgogala.byethost5.com

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Thread

Joining two tables using *two* columns (instead of one) Mateusz <no@spam.please> - 2012-04-05 15:21 +0200
  Re: Joining two tables using *two* columns (instead of one) Lennart Jonsson <erik.lennart.jonsson@gmail.com> - 2012-04-05 16:30 +0200
    Re: Joining two tables using *two* columns (instead of one) Mateusz <no@spam.please> - 2012-04-05 18:01 +0200
      Re: Joining two tables using *two* columns (instead of one) Robert Klemme <shortcutter@googlemail.com> - 2012-04-05 23:16 +0200
        Re: Joining two tables using *two* columns (instead of one) Mladen Gogala <gogala.mladen@gmail.com> - 2012-04-06 01:00 +0000
          Re: Joining two tables using *two* columns (instead of one) Jasen Betts <jasen@xnet.co.nz> - 2012-04-06 04:12 +0000
            Re: Joining two tables using *two* columns (instead of one) Mladen Gogala <gogala.mladen@gmail.com> - 2012-04-06 04:44 +0000
              Re: Joining two tables using *two* columns (instead of one) Robert Klemme <shortcutter@googlemail.com> - 2012-04-06 14:17 +0200
                Re: Joining two tables using *two* columns (instead of one) Mladen Gogala <gogala.mladen@gmail.com> - 2012-04-08 19:01 +0000
    Re: Joining two tables using *two* columns (instead of one) Jasen Betts <jasen@xnet.co.nz> - 2012-04-05 21:20 +0000
      Re: Joining two tables using *two* columns (instead of one) Lennart Jonsson <erik.lennart.jonsson@gmail.com> - 2012-04-06 09:30 +0200
        Re: Joining two tables using *two* columns (instead of one) Jasen Betts <jasen@xnet.co.nz> - 2012-04-06 23:42 +0000
        Re: Joining two tables using *two* columns (instead of one) Lennart Jonsson <erik.lennart.jonsson@gmail.com> - 2012-04-08 20:39 +0200
  Re: Joining two tables using *two* columns (instead of one) Mladen Gogala <gogala.mladen@gmail.com> - 2012-04-05 19:48 +0000
    Re: Joining two tables using *two* columns (instead of one) Mladen Gogala <gogala.mladen@gmail.com> - 2012-04-05 19:50 +0000
    Re: Joining two tables using *two* columns (instead of one) Mateusz <no@spam.please> - 2012-04-06 09:13 +0200
  Re: Joining two tables using *two* columns (instead of one) Jasen Betts <jasen@xnet.co.nz> - 2012-04-05 21:28 +0000
    Re: Joining two tables using *two* columns (instead of one) Mateusz <no@spam.please> - 2012-04-06 09:00 +0200
      Re: Joining two tables using *two* columns (instead of one) Jasen Betts <jasen@xnet.co.nz> - 2012-04-06 23:38 +0000
  Re: Joining two tables using *two* columns (instead of one) Mateusz <no@spam.please> - 2012-04-06 08:48 +0200
    Re: Joining two tables using *two* columns (instead of one) Robert Klemme <shortcutter@googlemail.com> - 2012-04-06 14:33 +0200
      Re: Joining two tables using *two* columns (instead of one) Mladen Gogala <gogala.mladen@gmail.com> - 2012-04-11 03:21 +0000
    Re: Joining two tables using *two* columns (instead of one) Torsten Kirschner <torsten.kirschner@gmail.com> - 2012-04-10 05:58 +0200
      Re: Joining two tables using *two* columns (instead of one) Fredrik Jonson <fredrik@jonson.org> - 2012-04-10 08:53 +0000
        Re: Joining two tables using *two* columns (instead of one) Torsten Kirschner <torsten.kirschner@gmail.com> - 2012-04-11 00:06 +0200
          Re: Joining two tables using *two* columns (instead of one) Robert Klemme <shortcutter@googlemail.com> - 2012-04-12 20:38 +0200

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