EJB3-QL has been heavily inspired by HQL, the native Hibernate Query Language. Both are therefore very close to SQL, but portable and independent of the database schema. People familiar with HQL shouldn't have any problem using EJB-QL. Actually, you use the same query API for EJB-QL and HQL queries. Portable EJB3 applications however should stick to EJB-QL or similar vendor extensions are needed.