> where ((:inputfilter is null) or (... = :inputfilter))
>
> if i use this kind of statement in my SP to dynamically assign
> optional filters does this mean the SP is not optimised?

I don't know the technical details of how Firebird optimizes these queries,
but I use this very same condition in one of my SPs and the performance is
MUCH worse than the performance without OR. Still, this is the best solution
I know of :-((

Pepak