I think complicate queries are not alowed on HF
HF is not a SQL based DB, and (in my opinion) not a real database at all.
You should make a Hread() - HAdd() loop I guess.
Or make an Insert-One-Row loop with the result of a select query.
(wich is very slow if there are lots of rows...)
Sorry, that's one of the reasons I chose not to use HF anymore.