I'm aware of that. However, it only has to be memorable for the period of time you're working with a query. If you open up an old view or stored procedure to modify it, you would read the table aliases first. If someone wasn't able to retain the meaning of 'S' and 'ST' for the length of time needed to modify a query then perhaps working with code isn't for them.
Lastly, if someone did have poor memory they could lengthen the aliases to STA and STU.
Better :) But I prefer to just give my tables short names to begin with. How about staff and pupils? That's so short that there is little temptation to abbreviate.
Lastly, if someone did have poor memory they could lengthen the aliases to STA and STU.