> Sorry, I couldn't test as my actual query is more complex and uses a
> view. The plan generated by Firebird refers to indexes within the view,
> but when I try to use it with the query I get an error message that the
> index is for a table that is not in the query (of course not, it's
> hidden within the view).

I'm not sure you can specify PLAN for VIEW internals...

> It turns out I don't need to specify a plan. If I remove the problem
> constraint (which was to return results on only one customer) it returns
> 100 times quicker, and it's easy within Crystal Reports to only display
> the customer I care about.

It is always better to not specify explicit PLAN ;)

Regards,
Vlad