EJB QL or EJB-QL is a portable database query language for Enterprise Java Beans.
EJB QL is a database query language similar to SQL.
In other words, EJB QL queries do not use tables and their components, but enterprise beans, their persistent state, and their relationships.
The result of an SQL query is a set of rows with a fixed number of columns.
One has to understand the data model of enterprise beans in order to write effective queries.