Date: Tue, 10 Aug 2010 21:44:33 +0200
From: Andreas Kretschmer <akretschmer@spamfence.net>
To: pgsql-sql@postgresql.org
Subject: Re: Duplicate rows
Message-ID: <20100810194433.GA2021@tux>
References: <00b701cb38c0$d64fc760$82ef5620$@com>
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Edward W. Rouse <erouse@comsquared.com> wrote:

> Is there any way to remove a duplicate row from a table? Not my db but I have
> to work with it. On version 7.4 right now.
> 

How to select the right records?

You can try to use the ctid-column, see my simple example:

test=# select * from dups ;
 i
---
 1
 1
 1
 2
 2
 3
 4
(7 Zeilen)

Zeit: 0,145 ms
test=*# delete from dups where (ctid, i) not in (select max(ctid), i from dups group by i);
DELETE 3
Zeit: 0,378 ms
test=*# select * from dups ;
 i
---
 1
 2
 3
 4
(4 Zeilen)


Andreas
-- 
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