From: Richard Huxton <dev@archonet.com>
To: Walter Cruz <walter.php@gmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: "for SELECT DISTINCT, ORDER BY expressions must appear in select list" - is that the standart or a limitation of postgresql?
Date: Thu, 15 Feb 2007 13:35:18 +0000
Message-ID: <45D46196.2090003@archonet.com> (raw)
In-Reply-To: <32cabba0702150319v427d5a25s9a6c7f851576baa2@mail.gmail.com>
References: <32cabba0702150319v427d5a25s9a6c7f851576baa2@mail.gmail.com>
Walter Cruz wrote:
>
> SELECT distinct name from test order by number
>
> (well, I think that que query doesn't make any sense, but raises the
> error :) )
>
> The error: ERROR: for SELECT DISTINCT, ORDER BY expressions must
> appear in select list is due to a standart implementarion or a design
> decision of postgres?
I think ORDER BY is defined to take place after DISTINCT, which means
there is no meaningful "number" for it to order by. You could
arbitrarily choose the first number encountered, but I can't see what
sense it would make to order by them.
--
Richard Huxton
Archonet Ltd
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To: pgsql-sql@postgresql.org
Cc: dev@archonet.com, walter.php@gmail.com
Subject: Re: "for SELECT DISTINCT, ORDER BY expressions must appear in select list" - is that the standart or a limitation of postgresql?
In-Reply-To: <45D46196.2090003@archonet.com>
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