nhibernate - 使用连接表的别名创建 SqlProjection

Question

我有这种情况:

public class AnswerSet {
public virtual IList<Answer> Answers {set; get;}
}

session.CreateCriteria<AnswerSet>()
        .CreateAlias( "Answers", "a" )
        .SetProjection( Projections.ProjectionList()
          .Add( Projections.GroupProperty( "TopicId" ), "TopicId" )
          .Add( Projections.GroupProperty( "TopicName" ), "TopicName" )
          .Add( Projections.SqlProjection( "count (case **{a}**.numerical_answer
when 1 then 1 when -1 then 1 else null end) as YesAnswers",
         new[] { "YesAnswers" }, new IType[] { NHibernateUtil.Int32 } ), "YesAnswers" )

如何指定子集合别名？
{a}.numeric_answer 不工作和 {别名} 指的是答案集。

SQL等价物是

select
      [as].topic_id as TopicId
      , [as].topic_name as TopicName
      , count (case [a].numerical_answer
               when 1 then 1
               when -1 then 1
               else null
               end) as YesAnswers
from answer_set [as] join answer [a] on [a].answer_set_id = [as].id

谢谢，
丹尼尔

Answer 1

如 numerical_answer不会出现在您的查询中的其他任何地方，您可以跳过表名，例如

"count (case numerical_answer when 1 then 1 when -1 then 1 else null end) as YesAnswers"