I would write a external function which does the evaluation you want.
this would be a module such as the FreeUDFLib.

Olivier Olmer

--- In firebird-support@yahoogroups.com, "peter_jacobi.rm"
<peter_jacobi@g...> wrote:

> For implementing incremental search in a GUI,
> I'm looking how to write a SELECT, which will
> find all rows where a columns starts with a
> specific string (as in LIKE('abc%')), but taking
> into account only primary character differences
> (disregarding case and accents).
>
> I'm aware of using David Schnepper's work on
> nocase and nocase/noaccent collations, but after
> thinking again about the problem, it seems better
> to try to solve the problem without them (as I want
> the output sorted according all differences).
>
> What's missing so far is a method how to 'increment'
> the search string to next string of equal length sorting
> higher according to primary differences.
>
> This 'incrementing' would return 'abd' for 'abc', and 'ac_' or
> 'abä' (depending on locale, err... collation) for 'abz'.
>
> Having this incremented string the query would like
> (:search holding the looked for string, :next holding
> the incremented string):
>
> > select col from t where
> > (col >= upper(:search) or col >= lower(:search)) and
> > col < upper(:next) and col < lower(:next);
>
> The upper/lower thing must be done as it varies from collation
> to collation which casing sorts lower. I hope it don't vary
> from collation to collation that the unaccented letter sort
> lower.
>
> Any ideas for implementing the 'increment'?
>
> Any alternatives for this requirements?
>
> Best Regards,
> Peter Jacobi,
> Hamburg, Germany