From: mnikulyak@gmail.com
To: pgsql-docs@postgresql.org
Subject: Should the cartesian product be more easily seen?
Date: Tue, 07 Mar 2017 20:57:21 +0000
Message-ID: <20170307205721.25051.30046@wrigleys.postgresql.org> (raw)
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The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/9.6/static/tutorial-join.html
Description:
In section "Chapter 2. The SQL Language", there are two "Exercises" for the
learner to try to do.
My note is about the first one. There, the correct answer is the cartesian
product of the sets of all records from the two joined tables.
Now, if the reader knows the solution then all is well and s/he is not
surprised with the output.
Should they have guessed wrong, however, then, chances are, they will not be
able to figure out the "cartesian product" idea from the output they will
see. The reason is that the 'cities' table contains only one record in it.
If there were at least two records in that table then the solving approach
would have been much more expressive. - IMHO...
Thanks for your great job!!
Best regards.
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To: pgsql-docs@postgresql.org
Cc: mnikulyak@gmail.com
Subject: Re: Should the cartesian product be more easily seen?
In-Reply-To: <20170307205721.25051.30046@wrigleys.postgresql.org>
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