I have tried it in 2.0 and 2.5 version. I have the problem in both.

--- In firebird-support@yahoogroups.com, Paul Vinkenoog <paul@...> wrote:
>
> Hi kokok,
>
> >> CAST(OrderDate + CAST((LfAvgDays+0.5) AS INTEGER) AS DATE) BETWEEN '2009/1/1' AND '2010/1/1'
>
> > Anyway: you can't cast dates to integers.
>
> Sorry, misread you SQL!
>
> The BETWEEN should definitely work!
>
> Which version and dialect of Firebird are you using?
>
>
> Paul Vinkenoog
>