下面是我的两个实体：

@Entity
@Table(name = "aog_reference")
public class AogReference
{
    @OneToOne(fetch = FetchType.LAZY, mappedBy="aogReference", cascade=CascadeType.ALL, optional=true)
    private Pack pack;

}

@Entity
@Table(name = "pack")
public class Pack
{

    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name="aog_reference")   
    private AogReference aogReference;

}

我可以使用Hibernate读写这两个实体，并且AogReference的***pack***属性被正确填充。
但是，我正在尝试运行一个HQL查询，该查询包含AogReference实体，而这些实体没有包引用它们。
在读了大量关于这方面的材料后，我希望这能起作用：

SELECT e FROM AogReference AS e left join e.pack  WHERE  (e.pack IS NULL)

但是我得到0行返回，即使我知道有AogReference实体没有任何来自Pack实体的引用。
我看过上面的hql生成的SQL，它看起来像这样：

select
        aogreferen0_.id as id1_0_,
        aogreferen0_.active as active2_0_,
        aogreferen0_.created as created3_0_,
        aogreferen0_.modified as modified4_0_,
        aogreferen0_.version as version5_0_,
        aogreferen0_.aog_delivery_number as aog_deli6_0_,
        aogreferen0_.aog_destination as aog_dest7_0_,
        aogreferen0_.aog_notes as aog_note8_0_,
        aogreferen0_.foc_notification_time as foc_noti9_0_,
        aogreferen0_.is_collection_today as is_coll10_0_,
        aogreferen0_.is_used as is_used11_0_,
        aogreferen0_.work_stream as work_st12_0_ 
    from
        aog_reference aogreferen0_ 
    left outer join
        pack pack1_ 
            on aogreferen0_.id=pack1_.aog_reference 
    where
        aogreferen0_.id is null

或简化：

select * 
 from 
   aog_reference a 
 left outer join 
    pack p on a.id = p.aog_reference 
 where a.id is null

现在请注意这个巨大的错误：

where a.id is null

Hibernate完全搞错了，生成的sql应该是这样的：

select
        aogreferen0_.id as id1_0_,
        aogreferen0_.active as active2_0_,
        aogreferen0_.created as created3_0_,
        aogreferen0_.modified as modified4_0_,
        aogreferen0_.version as version5_0_,
        aogreferen0_.aog_delivery_number as aog_deli6_0_,
        aogreferen0_.aog_destination as aog_dest7_0_,
        aogreferen0_.aog_notes as aog_note8_0_,
        aogreferen0_.foc_notification_time as foc_noti9_0_,
        aogreferen0_.is_collection_today as is_coll10_0_,
        aogreferen0_.is_used as is_used11_0_,
        aogreferen0_.work_stream as work_st12_0_ 
    from
        aog_reference aogreferen0_ 
    left outer join
        pack pack1_ 
            on aogreferen0_.id=pack1_.aog_reference 
    where
        pack1_.id is null

请注意，最后一行现在是：

where pack1_.id is null

Hibernate生成的sql在应该检查Pack的id时却在检查AogReference上的id。
当我在我的数据库中启动它时，纠正后的sql工作正常。
在我看来，这就像是Hibernate中的一个巨大的bug，它根本没有生成正确的SQL。
任何意见（明智的）感激地收到。
谢谢你，
艾德
更新：看起来这是一个hibernate bug，它从2010年就已经存在了。