> do you now a udf function i can declare in firebird 1.5 ?
>
> i would like to find some data by searching on a date field format.
>
> i would like to extract all data for a periode,
> for example a periode from 12 july to 24 september.
> of course i want the query to return data for all years.
>
> i can do it by shaking month + day function,
> but it would be more difficult to do.

Look at builtin function
EXTRACT(YEARDAY FROM yourfield)

Do you require the select to use index ?

Ivan