Nhibernate 3 Linq抛出Antlr.Runtime.NoViableAltException。[英] Nhibernate 3 Linq throws Antlr.Runtime.NoViableAltException

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问题描述

使用 NHibernate 3 linq 提供程序,我想选择子项的最大计数.

使用以下 linq 查询,我得到一个 Antlr.Runtime.NoViableAltException,后跟一个 Antlr.Runtime.MismatchedTreeNodeException

int maxCount = _repository.FindAll<Device>().Max(d=>d.DeviceSensors.Count());

存储库函数 FindAll() 返回 session.Query.

异常详情:

Antlr.Runtime.NoViableAltException occurred
  Message="Exception of type 'Antlr.Runtime.NoViableAltException' was thrown."
  Source="NHibernate"
  Char=0
  CharPositionInLine=-1
  Index=21
  Line=0
  UnexpectedType=84
  StackTrace:
       at NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.aggregateExpr() in d:\CSharp\NH\nhibernate\src\NHibernate\Hql\Ast\ANTLR\Generated\HqlSqlWalker.cs:line 3203
  InnerException: 

.

Antlr.Runtime.MismatchedTreeNodeException occurred
  Message="Exception of type 'Antlr.Runtime.MismatchedTreeNodeException' was thrown."
  Source="Antlr3.Runtime"
  Char=0
  CharPositionInLine=-1
  Index=21
  Line=0
  UnexpectedType=84
  StackTrace:
       at Antlr.Runtime.Tree.TreeParser.RecoverFromMismatchedToken(IIntStream input, Int32 ttype, BitSet follow)
       at Antlr.Runtime.BaseRecognizer.Match(IIntStream input, Int32 ttype, BitSet follow)
       at NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.functionCall() in d:\CSharp\NH\nhibernate\src\NHibernate\Hql\Ast\ANTLR\Generated\HqlSqlWalker.cs:line 7906
  InnerException:
<小时>
 NHibernate.Hql.Ast.ANTLR.QuerySyntaxException: Exception of type 'Antlr.Runtime.NoViableAltException' was thrown. [.First(.Select(.OrderByDescending(NHibernate.Linq.NhQueryable`1[RGB.TTT.Domain.Device], Quote((x, ) => (x.DeviceSensors.Count)), ), Quote((x, ) => (new <>f__AnonymousType2`1(x.DeviceSensors.Count, ))), ), )]

这是一个已知问题吗?还是我必须重写查询,欢迎提出任何建议.

推荐答案

显然当前的 NHibernate Linq 提供程序无法在 Select 子句中结合 Max() 和内部 Select.您可能需要将 Max 从 Query 中拉出并在之后应用它,例如

int maxCount = session.Query<Device>()
    .Select(d => d.DeviceSensors.Count)
    .ToList()
    .Max();

没有子选择的更简单的版本可以工作:

int maxCount = session.Query<Device>()
    .Select(d => d.Name.Length)
    .Max();

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问题描述

Using the NHibernate 3 linq provider I would like to select the max count of an items children.

Using the following linq query I get an Antlr.Runtime.NoViableAltException followed by an Antlr.Runtime.MismatchedTreeNodeException

int maxCount = _repository.FindAll<Device>().Max(d=>d.DeviceSensors.Count());

The repository function FindAll() returns session.Query.

Exception details:

Antlr.Runtime.NoViableAltException occurred
  Message="Exception of type 'Antlr.Runtime.NoViableAltException' was thrown."
  Source="NHibernate"
  Char=0
  CharPositionInLine=-1
  Index=21
  Line=0
  UnexpectedType=84
  StackTrace:
       at NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.aggregateExpr() in d:\CSharp\NH\nhibernate\src\NHibernate\Hql\Ast\ANTLR\Generated\HqlSqlWalker.cs:line 3203
  InnerException: 

.

Antlr.Runtime.MismatchedTreeNodeException occurred
  Message="Exception of type 'Antlr.Runtime.MismatchedTreeNodeException' was thrown."
  Source="Antlr3.Runtime"
  Char=0
  CharPositionInLine=-1
  Index=21
  Line=0
  UnexpectedType=84
  StackTrace:
       at Antlr.Runtime.Tree.TreeParser.RecoverFromMismatchedToken(IIntStream input, Int32 ttype, BitSet follow)
       at Antlr.Runtime.BaseRecognizer.Match(IIntStream input, Int32 ttype, BitSet follow)
       at NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.functionCall() in d:\CSharp\NH\nhibernate\src\NHibernate\Hql\Ast\ANTLR\Generated\HqlSqlWalker.cs:line 7906
  InnerException:

 NHibernate.Hql.Ast.ANTLR.QuerySyntaxException: Exception of type 'Antlr.Runtime.NoViableAltException' was thrown. [.First(.Select(.OrderByDescending(NHibernate.Linq.NhQueryable`1[RGB.TTT.Domain.Device], Quote((x, ) => (x.DeviceSensors.Count)), ), Quote((x, ) => (new <>f__AnonymousType2`1(x.DeviceSensors.Count, ))), ), )]

Is this a known problem? Or do I have to rewrite the query, any suggestions are more then welcome.

推荐答案

Apparently the current NHibernate Linq provider cannot combine Max() and an inner Select in the Select clause. You may need to pull the Max out of the Query and apply it afterwards, e.g.

int maxCount = session.Query<Device>()
    .Select(d => d.DeviceSensors.Count)
    .ToList()
    .Max();

A simpler version without a sub select works:

int maxCount = session.Query<Device>()
    .Select(d => d.Name.Length)
    .Max();