> I have newbie question:
> is it possible to declare explicitly size of the index on [var]char

column?

> When I have ie. varchar(255), can I specify index for sorting only from
> i.e. first 5 letters?
> Something like create index xx on tablee(myvarchar(5));

You need to discuss SQL specifics in firebird-support as there will be
lots more help, but method I use is to have a second field in the
table and populate it from a trigger. The index then goes on the
shorter field, and you can 'play' with the exact data that goes in the
field. I combine office, type, and ticket number to give a simple
order function which I can adjust as required, rather than having fun
with GROUP and ORDER BY lines :)