I rarely use aliases (unless rarely required in self-join queries). When I have that option, I create unique columns by prefixing every table (and its objects) with a number. Something like: Create table T1234_Employee (C1234_Employee_id number(5), C1234_employee_status char(1)...) Index X1234_Employee_Id on .... Etc.
Yes, the column names may be longer this way, but easy to refer to and easy to communicate (by specifying a table number). I wonder what others think about it. David. -----Original Message----- From: Rik Wasmus [mailto:r...@grib.nl] Sent: Wednesday, August 03, 2011 6:47 AM To: mysql@lists.mysql.com Subject: Re: Too many aliases > >>>> 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 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=dle...@us.univision.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
