C# NHibernate与linq左连接

我需要将使用NHibernate的linq中的连接更改为左外连接。 我的代码是这样的

IQueryable<DimServicePoint> spq =
                            from sp in session.Query<DimServicePoint>()
                            join spm in session.Query<DimServicepointMeter>() on sp.ServicePointKey equals spm.ServicePointKey into gj
                            from subsp in gj.DefaultIfEmpty()
                            where (sp.ServicePointID == servicePointID && sp.DimAccount.AccountKey != 0 && sp.StartDayID <= currentDateId && sp.EndDayID >= currentDateId)
                            select sp;

IQueryable spq=
来自会话中的sp.Query（）
将sp.ServicePointKey上的session.Query（）中的spm加入gj
来自gj.DefaultIfEmpty（）中的subp
其中（sp.ServicePointID==ServicePointID&&sp.dimcount.AccountKey！=0&&sp.StartDayID=currentDateId）
选择sp；

现在，我的要求是在这个查询中使用左连接连接DimServicepointMeter。 等效的SQL查询是：

select * from dw.dim_servicepoint sp
left join dw.dim_servicepoint_meter spm on sp.servicepointkey = spm.servicepointkey
where sp.servicepointid = @ServicePointID  and sp.accountkey != 0
and sp.startdayid <= @currentDateId  and sp.enddayid >= @currentDateId 

从dw.dim_servicepoint sp选择*
左连接dw.dim\u servicepoint\u sp.servicepointkey=spm.servicepointkey上的仪表spm
其中sp.servicepointid=@servicepointid和sp.accountkey！=0
和sp.startdayid=@currentDateId

我在NHibenate或linq没有太多的工作，所以我不知道如何在NHibenate或linq中加入左撇子。

---

非常感谢您的帮助

中当前不支持任意左连接（v4.1）。它们转换为LINQ，与一起使用时抛出

NotImplementedException

如链接方式中所述，您可以使用。普通也可以（使用θ样式联接）

您可以将仪表映射到服务点上。它看起来像（没有您的

DimAccount

属性）：

结果查询将使用左联接

注：
我个人避免使用类似LINQSQL的语法，我喜欢使用LINQ扩展方法，如我的答案所示。我发现它们更具可读性。
我更喜欢使用NHibernate进行延迟加载，而不是急于加载，因为它可以批量加载延迟加载。正如我所解释的，它倾向于在保持良好性能的同时简化代码

public class DimServicePoint
{
    public virtual int ServicePointID { get; set; }
    public virtual int StartDayID { get; set; }
    public virtual int EndDayID { get; set; }
    public virtual int ServicePointKey { get; set; }
    public virtual ISet<DimServicePointMeter> ServicePointMeters { get; set; }
}

public class DimServicePointMeter
{
    public virtual int ServicePointMeterID { get; set; }
    public virtual int ServicePointKey { get; set; }
}

<class name="DimServicePoint">
    <id name="ServicePointID">
        <generator class="assigned" />
    </id>
    <property name="StartDayID" />
    <property name="EndDayID" />
    <property name="ServicePointKey" />

    <set name="ServicePointMeters" inverse="true" batch-size="20">
        <key column="ServicePointKey" property-ref="ServicePointKey" />
        <one-to-many class="DimServicePointMeter" />
    </set>
</class>
<class name="DimServicePointMeter">
    <id name="ServicePointMeterID">
        <generator class="assigned" />
    </id>
    <property name="ServicePointKey" />
</class>

var spq = session.Query<DimServicePoint>()
    .Where(sp => sp.ServicePointID == servicePointID && sp.DimAccount.AccountKey != 0 &&
        sp.StartDayID <= currentDateId && sp.EndDayID >= currentDateId);

var spq = session.Query<DimServicePoint>()
    .Where(sp => sp.ServicePointID == servicePointID && sp.DimAccount.AccountKey != 0 &&
        sp.StartDayID <= currentDateId && sp.EndDayID >= currentDateId)
    .FetchMany(sp => sp.ServicePointMeters);