From: Phillip Gawlowski <cmdjackryan@...>
Date: 2010-11-20T00:24:43+09:00
Subject: Re: Where to start from?

On Fri, Nov 19, 2010 at 3:06 PM, Mike Stephens <rubfor@recitel.net> wrote:
>
> I therefore take issue with your point that you need to know maths set
> theory to appreciate SQL. It was designed to be simple to understand
> without a spec!alist background.

Without set theory, math doesn't work. Any number space is a set (the
set of rational numbers, the set of real numbers, the set of complex
numbers). It's necessary to represent solutions (which can be an
interval from -infinity to infinity, or a set with a single element,
or anything in between), and a set can be all white Ford F-150s in
Washington, D.C. with a Senate numberplate.

As far as mathematical principles go, set theory is neither
specialist, nor advanced.

And without an understanding what sets are, and how they relate to
JOINs, you won't be able to test your assumptions about a JOIN for
correctness.

-- 
Phillip Gawlowski

Though the folk I have met,
(Ah, how soon!) they forget
When I've moved on to some other place,
There may be one or two,
When I've played and passed through,
Who'll remember my song or my face.