> I've asked that question myself and many others, and still I couldn't
> find those discussions. I know Ann gave a good point as to why it
> wasn't implemented yet.
>
> But, I think with the introduction of aliases in FB 1.5, it might be
> one small step forward for this feature to be implemented. But,
> there's a lot more work to do to get there. If my memory serves me
> well, the biggest hurdle in cross database selection is to be able to
> get the proper optimization of the data retrieval and proper
> synchronization of the data retrieval between the databases, and
> having a common cache between the databases for the result set.
>
> So I believe that the task at hand is not small and would require
> quite some work and a very good knowledge of the engine.

1. The functionality is there at the embedded SQL layer and the API
2. Its also there in GDML (QLI)
3. Its not surfaced in the SQL layer
4. Firebird supports the concept of database handles to allow you to
manipulate multiple databases at a time within queries....
5. And yes - it could be surfaced, but its a non trivial task.

Regards
Paul