title: NHibernate HQL queries
body: <p>How to write HQL queries using NHibernate. What namespaces will I have to included so that everything works fine. Actually I have 2 tables Ticket and Trip and I wanta count of all the records in Trip that do not have a corresponding entry in Ticket. There is a tid field in ticket that refrences Trip id. Can anybody please explain me from start how will I write a NHibernate HQL query for this?</p>