LINQ To NHibernate 忽略“分组依据”条款

Question

我使用 NHibernate 3.2.0，我无法让 LINQ 提供程序为此语句生成正确的 SQL 查询：

var result = (from translation in session.Query<TmTranslation>()
              where translation.Id > 0
              group translation by translation.Language into grp
              select new { Lang = grp.Key.Code }).ToList();

生成的 SQL

select tmtranslat0_.id                        as id32_,
       tmtranslat0_.status                    as status32_,
       tmtranslat0_.text                      as text32_,
       tmtranslat0_.last_revision             as last4_32_,
       tmtranslat0_.fk_id_translation_unit    as fk5_32_,
       tmtranslat0_.fk_id_translator          as fk6_32_,
       tmtranslat0_.fk_id_last_modifier       as fk7_32_,
       tmtranslat0_.fk_id_last_match_category as fk8_32_,
       tmtranslat0_.fk_id_language            as fk9_32_
from   "TRANSLATION" tmtranslat0_
where  tmtranslat0_.id > 0

当然会导致从数据库加载所有实体并将结果集分组到内存中（结果本身）是正确的）。

我希望

select tmtranslat0_.fk_id_language
from   "TRANSLATION" tmtranslat0_
where  tmtranslat0_.id > 0
group by tmtranslat0_.fk_id_language

生成这样的东西。

我错过了什么吗？

非常感谢。

Answer 1

我唯一可以建议的是使用 QueryOver API。