From: Joe <dev@freedomcircle.net>
To: Gavin 'Beau' Baumanis <gavinb@eclinic.com.au>
Cc: pgsql-sql@postgresql.org
Subject: Re: Select into
Date: Thu, 20 Mar 2008 08:10:47 -0400
Message-ID: <47E25447.6040109@freedomcircle.net> (raw)
In-Reply-To: <786D2B38-CE0A-41BF-9E70-4DEB22F8D9EF@eclinic.com.au>
References: <94F93C0F-DA95-4435-B253-57C90961DF34@eclinic.com.au>
<20080320104922.GB18935@a-kretschmer.de>
<65937bea0803200358i290bdc87hdeca777b593b5df1@mail.gmail.com>
<786D2B38-CE0A-41BF-9E70-4DEB22F8D9EF@eclinic.com.au>
Gavin 'Beau' Baumanis wrote:
>
> The copy is inside the same table, so I don't understand why it (the
> required query ) would require any joins.
>
> Ie. I want to copy the contents of a row (but for the id column - of
> course) into a record in the same table.
I think what you want is something like this:
Given (col1 being the id or PK):
col1 | col2 | col3
------+------+---------------
1 | 123 | first record
2 | 456 | second record
3 | 789 | third record
then
update t1 set col2 = t1copy.col2, col3 = t1copy.col3
from t1 as t1copy
where t1.col1 = 1 and t1copy.col1 = 3;
will result in:
col1 | col2 | col3
------+------+---------------
1 | 789 | third record
2 | 456 | second record
3 | 789 | third record
So, it is a join ... of a table with a virtual copy of itself.
Joe
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To: pgsql-sql@postgresql.org
Cc: dev@freedomcircle.net, gavinb@eclinic.com.au
Subject: Re: Select into
In-Reply-To: <47E25447.6040109@freedomcircle.net>
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