使用具有相同列名的连接表时没有别名的Hibernate意外结果

Question

我正在使用hibernate 3.2.6-GA，hibernate-core 3.3.2-GA。

我有以下数据

TABLE_A :               TABLE_ B:

B1 | B2                 ID | CODE
-------                 ---------
1  | 2                   1 | AAA
                         2 | BBB

我想理解为什么以下由Hibernate管理的 SQL查询

StringBuffer sb = new StringBuffer();
sb.append("SELECT ");
sb.append(" b1.CODE, ");
sb.append(" b2.CODE ");
sb.append("FROM TABLE_A a ");
sb.append(" JOIN TABLE_B b1 ON b1.id = a.B1 ");
sb.append(" JOIN TABLE_B b2 ON b2.id = a.B2 ");

Query query = sessionFactory.getCurrentSession().createSQLQuery(sb.toString());

List<Object> results = query.list();     

返回以下结果：

 [[AAA, AAA]]

而我使用 SQL别名：

StringBuffer sb = new StringBuffer();
sb.append("SELECT ");
sb.append(" b1.CODE as code1, "); // here is the difference
sb.append(" b2.CODE as code2 ");
sb.append("FROM TABLE_A a ");
sb.append(" JOIN TABLE_B b1 ON b1.id = a.B1 ");
sb.append(" JOIN TABLE_B b2 ON b2.id = a.B2 ");

Query query = sessionFactory.getCurrentSession().createSQLQuery(sb.toString());

List<Object> results = query.list();  

返回以下结果：

 [[AAA, BBB]]