JPA - calculated column as entity class property?
===

Relatively new to JPA, so I have one kind of architectural question.
Let's say I have tables EMPLOYEE and DEPARTMENT with many to one relationship (i.e. many employees work for one department):

    EMPLOYEE
      EMPLOYEE_ID
      EMPLOYEE_NAME
      DEPARTMENT_ID 

    DEPARTMENT
      DEPARTMENT_ID
      DEPARTMENT_NAME

So I can define proper entities for Employee and Department, there's no problem. However, in one view I would like to display list of departments with number of employees working for that department, something like this:

    SELECT D.DEPARTMENT_NAME, 
           (SELECT COUNT(*) FROM EMPLOYEE E WHERE E.DEPARTMENT_ID = D.DEPARTMENT_ID) NUMBER_OF_EMPLOYEES
    FROM DEPARTMENT D

I'm just not sure what is the right strategy to accomplish this using JPA...
I don't want to always fetch number of employees for Department entity, as there is only one view when it is needed. 
