From: Rik Wasmus
Date: August 3 2011 10:46am
Subject: Re: Too many aliases
List-Archive: http://lists.mysql.com/mysql/225480
Message-Id: <201108031246.39913.rik@grib.nl>
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> >>>> 2011/08/02 12:11 +0530, Adarsh Sharma >>>>
> 
> select p.* from table A p, B q where p.id=q.id
> 
> or
> 
> select p.* from table B q , A p where q.id=p.id
> <<<<<<<<
> Why do people constantly change table names for queries, although, as here,
> it gain them nothing? It often makes for less clarity (for which table is
> this an alias???).

Depens on your table names. I rather like being able to give a short 
description rather then long table names if someone decided that as a 
tablename. I doubt your example with already short tablenames is one from real 
life, but if you saw someone doing it would indeed be a waste of time. But the 
main thing is it helps to distinguish tables  in joins having the same table 
more then once (and of course results from subqueries etc.):

SELECT first.* 
FROM tablename first
LEFT JOIN   tablename second
   ON    first.some_id = second.some_id
   AND first.id != second.id
WHERE second.id IS NULL
-- 
Rik Wasmus