Hibernate原生查询返回的数据读取问题

1、Hibernate用原生SQL查询数据，这里query.list() 返回的是一个 对象数组；而我却将一个对象数组转为 实体类对象list，这里报出 java.lang.ClassCastException （cannot be cast to com.entity.Employee)，这里就像有两个类（A类与B类） A a = new A()；  B  b  = (B)a；这样就会出这个异常。　　　　　

String sql = "SELECT " +
"e.employee_id, " +
"e.last_name, " +
"e.emall, " +
"e.salary " +
"FROM " +
"departments as d left join employess AS e " +
"ON d.department_id = e.department_id " +
"WHERE d.department_id = '2'";

SessionFactory sf = hibernateTemplate.getSessionFactory();
Session session=sf.openSession();
Query query = session.createSQLQuery(sql);
List<Employee> list = query.list();
for(Employee employee : list) {
　　System.out.println(employee.getLast_name());
}

　　解决办法：在  session.createSQLQuery(sql)后面加上 .addEntity(Employee.class) ，Employee 是实体类

String sql = "SELECT " +
"e.employee_id, " +
"e.last_name, " +
"e.emall, " +
"e.salary " +
"FROM " +
"departments as d left join employess AS e " +
"ON d.department_id = e.department_id " +
"WHERE d.department_id = '2'";

SessionFactory sf = hibernateTemplate.getSessionFactory();
Session session=sf.openSession();
Query query = session.createSQLQuery(sql).addEntity(Employee.class);
List<Employee> list = query.list();
for(Employee employee : list) {
　　System.out.println(employee.getLast_name());
}

2、上面写完启动项目测试时，遇到 java.sql.SQLException: Column 'department_id' not found. 这个错误，没有找到 department_id，意思就是在查询出来的结果集中没有 department_id这属性，在SQL中加上 e.department_id 就解决了这个问题。

String sql = "SELECT " + 
                    "e.employee_id, " + 
                    "e.department_id, " + 
                    "e.last_name, " + 
                    "e.emall, " + 
                    "e.salary " + 
                    "FROM " + 
                    "departments as d left join employess AS e " + 
                    "ON d.department_id = e.department_id " + 
                    "WHERE d.department_id = '2'";

解决完这个问题就能正常输出数据了，此篇幅为了学习，望大神多多指教