Re: SQL exception join: Left side now needs data combined from two tables -- MIDRANGE-L

Subject: Re: SQL exception join: Left side now needs data combined from two tables
From: Adam Glauser <adamglauser@xxxxxxxxxxxx>
Date: Wed, 02 Apr 2008 16:35:58 -0400
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Dan wrote:

Elvis, it seems odd that UNION would, by default (DISTINCT), weed out
duplicates. Is that the SQL standard? In this case, I don't think it
affects this query, as all records between the two tables are unique.

I hope you don't mind if I chime in here. I'm not sure, but I'd guess it's the SQL standard.

My understanding is that the UNION is based on the mathematical set-theory concept of a union. By definition, sets don't contain duplicate elements.

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