> I agree. It sounds similar to 0 being reported in a result column of a
> view on the right side of a left join where no match occurred (instead
> of what should obviously have been null).
>
> http://tracker.firebirdsql.org/browse/CORE-871
>
> The field is flagged as not null but there are null flag is set.

Yes, it is the same problem, the field is incorrectly reported as not nullable,
but actual result is correct (try with FSQL).

Ivan