Re: NATURAL JOIN without join columbs

From: Jon Heggland <heggland_at_idi.ntnu.no>
Date: Fri, 2 Sep 2005 09:01:09 +0200
Message-ID: <MPG.1d82172478021c599896fe@news.ntnu.no>

In article <g_LRe.349013$5V4.156421_at_pd7tw3no>, toledobythesea_at_oohay.ac says...
> while there may not be any common 'columns', some people say that there
> is always at least one common attribute, namely the empty set.

Nitpick:

There is always one (and only one) common /set of attributes/ (even if it is empty). That set, of course, is the intersection of the headings of the operands.

-- 
Jon

Received on Fri Sep 02 2005 - 02:01:09 CDT