Alphabetical by what? Table name, or order in the joins?
I suspect the latter. Which means in one query you might have
Order as a
Join OrderItem as b
And in another it might be
OrderLine as a
Join Order as b
Order as o
Join OrderLine as ol
OrderLine as ol
Join Order as o
Order is always o and OrderLine is always ol.
As far as short aliases (1 or 2 letters) I prefer them to keep the code compact.
In any organization there are certain key tables that are used over and over again in queries and views. I work in health insurance, so we have tables like Member, Provider, Claims, etc. In my code, these get the single letter aliases. Other tables being related would get longer aliases - but again I try to use the same for each one. That does run into complications from time to time - for example, is cd used for ClaimDiagnosis or ClaimDetailServiceLine? Sometimes the latter is cd, sometimes sl. I have a hard time following my own conventions.....