如何使用LINQ在Where子句中进行NHibernate子查询? [英] How to a NHibernate subquery in Where clause with LINQ?

问题描述

我试图在where子句中编写一个相关子查询，如下所示:

I'm trying to write a correlated subquery in the where clause like this:

var foo = from d in session.Query<Document>()
          where true == 
              ( from a in session.Query<ACLEntry>()
                where a.Id == d.Id || a.Id == null
                select a.Result
              ).FirstOrDefault()
          select d;

预期的SQL输出与此关于SO的未回答的问题非常相似.

我认为Linq语句本身很好，因为我可以使它在我正在制作原型的LinqPad中运行.但是NHibernate向我抛出了这些神秘的错误:

I think the Linq statement itself is fine because I can get it to run in LinqPad where I was prototyping. But NHibernate throws me these mysterious errors:

错误NHibernate.Hql.Parser [[null)]-NoViableAltException(86 @ [])

ERROR NHibernate.Hql.Parser [(null)] - NoViableAltException(86@[])

错误NHibernate.Hql.Parser [[null)]-MismatchedTreeNodeException(72！= 3)

ERROR NHibernate.Hql.Parser [(null)] - MismatchedTreeNodeException(72!=3)

这是NHibernate LINQ提供程序不支持的方案吗?关于如何重组查询以解决该问题的任何想法?

Is this an unsupported scenario with the NHibernate LINQ provider? Any ideas on how I might be able to restructure this query to get around it?

推荐答案

在解析查询的true == ...部分时可能会遇到一些麻烦.

It is probably having some trouble parsing the true == ... portion of the query.

可能想尝试一下，

var foo = from d in session.Query<Document>()
    where (from a in session.Query<ACLEntry>()
           where a.Id == d.Id || a.Id == null
           select a.Result
          ).FirstOrDefault()
    select d;

这篇关于如何使用LINQ在Where子句中进行NHibernate子查询?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！