From: | Andy Lewis <alewis(at)mpsi(dot)net> |
---|---|
To: | phd2(at)earthling(dot)net |
Cc: | pgsql-sql(at)postgreSQL(dot)org |
Subject: | Re: [SQL] Duplicate rows |
Date: | 1998-05-16 14:10:06 |
Message-ID: | Pine.LNX.3.95.980516090952.15079C-100000@shell.mpsi.net |
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Thread: | |
Lists: | pgsql-sql |
Thanks, I'll give it a try.
Andy
On Sat, 16 May 1998, Oleg Broytmann wrote:
>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(at)earthling(dot)net
> Programmers don't die, they just GOSUB without RETURN.
>
>
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