Re: [SQL] Duplicate rows
Oleg Broytmann <phd@comus.ru>
From: Oleg Broytmann <phd@comus.ru>
To: Andy Lewis <alewis@mpsi.net>
Cc: pgsql-sql@postgreSQL.org
Date: 1998-05-16T14:06:06Z
Lists: pgsql-sql
Hi!
On Sat, 16 May 1998, Andy Lewis wrote:
> Right, I know that there are dups in the column. But, I don't know where they
> are nor do I know their value(s). I want to be able to find, say, two interger
> values that are in the same column but, different rows.
It seems that you need a correlated subquery - a loop for every row, that
tests whether there are equal values.
SELECT oid, mycolumn FROM mytable a
WHERE mycolumn IN
(SELECT oid, mycolumn FROM mytable b
WHERE a.oid <> b.oid)
Or may be, join with the same table. Not sure what is better in this
situation.
SELECT oid, mycolumn FROM mytable a, mytable b
WHERE a.oid <> b.oid AND
a.mycolumn = b.mycolumn
In both cases "a.oid <> b.oid" excludes the same row from comparison (I
am pretty sure that in the same row a.mycolumn = b.column :).
Oleg.
----
Oleg Broytmann http://members.tripod.com/~phd2/ phd2@earthling.net
Programmers don't die, they just GOSUB without RETURN.