From: Joshua Tolley <eggyknap@gmail.com>
To: Frank Bax <fbax@sympatico.ca>
Cc: pgsql-sql@postgresql.org
Subject: Re: join returns too many results...
Date: Mon, 4 Oct 2010 07:24:39 -0600
Message-ID: <4ca9d59a.26798e0a.1059.25cf@mx.google.com> (raw)
In-Reply-To: <BLU0-SMTP934181715239A633CC970AAC6B0@phx.gbl>
References: <BLU0-SMTP934181715239A633CC970AAC6B0@phx.gbl>
On Sun, Oct 03, 2010 at 02:54:41PM -0400, Frank Bax wrote:
> Whatever clause I choose to add I *must* ensure that final result set
> contains only one-to-one join between tables. Either of these two
> results is acceptable:
>
> For option 1; result C=All or C=Centre is acceptable.
> For option 2; result B=NE70 or B=NE75 or B=NE80 is acceptable.
>
> I am lost trying to construct SQL to accomplish this...
Try DISTINCT ON, after ensuring the results are ordered meaningfully.
http://www.postgresql.org/docs/current/interactive/sql-select.html#SQL-DISTINCT
--
Joshua Tolley / eggyknap
End Point Corporation
http://www.endpoint.comAttachments:
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To: pgsql-sql@postgresql.org
Cc: eggyknap@gmail.com, fbax@sympatico.ca
Subject: Re: join returns too many results...
In-Reply-To: <4ca9d59a.26798e0a.1059.25cf@mx.google.com>
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