You need to use native SQL queries, there is no support for UNION in EJB-QL/JPA-QL/HQL. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4066889#4066889 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4066889