From: Edward W. Rouse <erouse@comsquared.com>
To: pgsql-sql@postgresql.org
Subject: Re: Duplicate rows
Date: Tue, 10 Aug 2010 16:42:48 -0400
Message-ID: <00c801cb38cc$9814b990$c83e2cb0$@com> (raw)
In-Reply-To: <20100810194433.GA2021@tux>
References: <00b701cb38c0$d64fc760$82ef5620$@com>
<20100810194433.GA2021@tux>
I am trying to test this but get an error.
select ctid, * from test where id < 3000000 order by id, ctid;
ERROR: could not identify an ordering operator for type tid
HINT: Use an explicit ordering operator or modify the query.
If I do a select I get this:
select ctid, * from test where id < 3000000 order by id;
ctid | id | activated | wake_up_time
(108,22) | 316 | f |
(36,17) | 316 | f |
(used 2 rows only for brevity
And when I tried max(ctid) I got:
ERROR: function max(tid) does not exist
HINT: No function matches the given name and argument types. You may need
to add explicit type casts.
I appreciate all the help and this feels like I'm almost there.
Thanks
Edward W. Rouse
-----Original Message-----
From: pgsql-sql-owner@postgresql.org [mailto:pgsql-sql-owner@postgresql.org]
On Behalf Of Andreas Kretschmer
Sent: Tuesday, August 10, 2010 3:45 PM
To: pgsql-sql@postgresql.org
Subject: Re: [SQL] Duplicate rows
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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unintentional side effect. (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly." (unknown)
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To: pgsql-sql@postgresql.org
Cc: erouse@comsquared.com
Subject: Re: Duplicate rows
In-Reply-To: <00c801cb38cc$9814b990$c83e2cb0$@com>
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