> > Is there some more detailed information available?
>
> You might ask in fb-devel. I don't know if you need to
> do something like:
>
> WHERE substring(mycol, 1, 100) = 'TEST'

Ok, here's some more info:
http://cvs.sourceforge.net/viewcvs.py/firebird/firebird2/doc/sql.extensions/README.expression_indices?view=markup

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server
Upscene Productions
http://www.upscene.com