Peter Bailey schrieb am 04.05.2010 um 16:28:38 (+1000):

> I would appreciate direction to a web site that will describe what is
> required wrt Table Aliases and what is considered to be best practice.
> (So far my searches have only found sites that show Table Aliases as
> being a nice option.)

For a self join, you need table aliases to tell different relations
apart:

SELECT T1.a FROM SOMETABLE T1
INNER JOIN SOMETABLE T2
ON ...

Same for other constructs (sub-selects) where the same table is referred
to more than once and you need to refer to a field of one of those parts
of the query.

--
Michael Ludwig