Svein,

> That Firebird doesn't know that 0 will be different from 1 without
> evaluating it for every row is actually helping those of us who
> occationally want to prevent the optimizer from choosing one
> particular plan.

Good point.

> I think you should take a look at the rdb$ tables. I may have done
> something that could be of use for you, but I don't remember whether I
> used SQL or methods that are part of IBO. Anyway, if I find the time
> tomorrow I will have a look when I get to work.

Thanks a lot Svein, but you don't have to bother. I know where to find the
info in sytem table. I just attempted to find something that would prevent
"them" change the logic that works for other data access technology.

Regards.

--
Jerome