NHibernate-linq查询（IQueryable）选择为匿名类型会产生较大的选择列表

Question

我正在尝试使用NHibernate.Linq的NHibernate Session.Query，并将其投影为匿名类型，但是当我检查references属性为null时，NHibernate添加了从主表和每个联接中选择每一列的列表。

Linq查询：

_session.Query<Allocation>()
    .Select(x => new
    {
        Id = x.Id,
        OwnerId = x.Owner != null ? x.Owner.Id : 0
    })
    .FirstOrDefault();

NHibernate SQL结果：

SELECT allocation0_.id        AS col_0_0_,
   contractor1_.id        AS col_1_0_,
   allocation0_.owner_id  AS col_2_0_,
   contractor1_.id        AS Id1_2_,
   contractor1_.symbol    AS symbol2_2_,
   contractor1_."name"    AS name3_2_,
   contractor1_.is_active AS is4_2_ 
FROM   allocation allocation0_
   LEFT OUTER JOIN contractor contractor1_
                ON allocation0_.owner_id = contractor1_.id 
LIMIT  1  

我知道可以通过使用QueryOver和投影列表来实现，但是我想知道为什么这种方式会生成错误的SQL结果