[rules-users] recursive queries

[Simon Chen]

Hi all,

I am wondering if it is possible to write more complex queries, e.g.,
running a query inside of a query. An example is that I have one query
to enumerate all books, and have another query to enumerate the people
that have not read all books.

According to a colleague of mine, the syntax for a query only allows
the entity LHS in its declaration:
http://docs.jboss.org/drools/release/5.2.0.CR1/drools-expert-docs/html/ch05.html#d0e5565

By definition, the entity LHS cannot contain the keyword query, as it
can only contain conditional elements:
http://docs.jboss.org/drools/release/5.2.0.CR1/drools-expert-docs/html/ch05.html#RuleLanguage-ConditionalElements

Any thoughts?

Thanks.
-Simon