Re: Warts with SELECT DISTINCT

From: Greg Stark <gsstark(at)mit(dot)edu>
To: Bruno Wolff III <bruno(at)wolff(dot)to>
Cc: Greg Stark <gsstark(at)mit(dot)edu>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Warts with SELECT DISTINCT
Date: 2006-05-04 04:05:16
Message-ID: 87d5eu1lkz.fsf@stark.xeocode.com
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Bruno Wolff III <bruno(at)wolff(dot)to> writes:

> > Whereas it shouldn't be hard to prove that this is equivalent:
> >
> > stark=> explain select col1 from test group by upper(col1),col1 order by upper(col1);
> > QUERY PLAN
> > ---------------------------------------------------------------------
> > Group (cost=88.50..98.23 rows=200 width=32)
> > -> Sort (cost=88.50..91.58 rows=1230 width=32)
> > Sort Key: upper(col1), col1
> > -> Seq Scan on test (cost=0.00..25.38 rows=1230 width=32)
> > (4 rows)
>
> I don't think you can assume that that will be true for any locale. If there
> are two different characters that both have the same uppercase version, this
> will break things.

No it won't.

--
greg

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