Adding multiple ORDER BY clauses to an NHibernate query throws exception

Question

Perhaps there's something wrong with my Linq query, or I'm running into something NHibernate doesn't support. Either way, this is a strange one. Here's my query that does work:

// Query for all ingredients, most used ingredients first
var ingredients = (from ing in session.Query<Ingredients>()
                   orderby ((from p in session.Query<RecipeIngredients>()
                            where p.Ingredient == ing
                            select p.RecipeIngredientId).Count()) descending
                   select new IngredientSource(ing.IngredientId, ing.DisplayName));

This produces the query:

select
   ingredient0_.IngredientId as col_0_0_,
   ingredient0_.DisplayName as col_1_0_
from ingredients ingredient0_
order by (select cast(count(recipeingr1_.RecipeIngredientId) as int4) from recipeingredients recipeingr1_ where recipeingr1_.IngredientId=ingredient0_.IngredientId) desc

I don't really like the weird cast() thing going on, but I doubt that slows anything down.

However, I need to add a second order by as well. The results need to be sorted by the ingredient name next. So I've tried the obvious:

var ingredients = (from ing in session.Query<Ingredients>()
                   orderby ((from p in session.Query<RecipeIngredients>()
                            where p.Ingredient == ing
                            select p.RecipeIngredientId).Count()) descending,
                            ing.DisplayName
                   select new IngredientSource(ing.IngredientId, ing.DisplayName));

This throws the exception:

NHibernate.Hql.Ast.ANTLR.QuerySyntaxException was unhandled
  HResult=-2146232832
  Message=Exception of type 'Antlr.Runtime.MismatchedTreeNodeException' was thrown. [.Select[KitchenPC.DB.Models.Ingredients,KitchenPC.Context.IngredientSource](.ThenBy[KitchenPC.DB.Models.Ingredients,System.String](.OrderByDescending[KitchenPC.DB.Models.Ingredients,System.Int32](NHibernate.Linq.NhQueryable`1[KitchenPC.DB.Models.Ingredients], Quote((ing, ) => (.Count[System.Guid](.Select[KitchenPC.DB.Models.RecipeIngredients,System.Guid](.Where[KitchenPC.DB.Models.RecipeIngredients](NHibernate.Linq.NhQueryable`1[KitchenPC.DB.Models.RecipeIngredients], Quote((p, ) => (Equal(p.Ingredient, ing))), ), Quote((p, ) => (p.RecipeIngredientId)), ), ))), ), Quote((ing, ) => (ing.DisplayName)), ), Quote((ing, ) => (new IngredientSource(ing.IngredientId, ing.DisplayName, ))), )]
  Source=NHibernate
  QueryString=.Select[KitchenPC.DB.Models.Ingredients,KitchenPC.Context.IngredientSource](.ThenBy[KitchenPC.DB.Models.Ingredients,System.String](.OrderByDescending[KitchenPC.DB.Models.Ingredients,System.Int32](NHibernate.Linq.NhQueryable`1[KitchenPC.DB.Models.Ingredients], Quote((ing, ) => (.Count[System.Guid](.Select[KitchenPC.DB.Models.RecipeIngredients,System.Guid](.Where[KitchenPC.DB.Models.RecipeIngredients](NHibernate.Linq.NhQueryable`1[KitchenPC.DB.Models.RecipeIngredients], Quote((p, ) => (Equal(p.Ingredient, ing))), ), Quote((p, ) => (p.RecipeIngredientId)), ), ))), ), Quote((ing, ) => (ing.DisplayName)), ), Quote((ing, ) => (new IngredientSource(ing.IngredientId, ing.DisplayName, ))), )
  StackTrace:
       at NHibernate.Hql.Ast.ANTLR.ErrorCounter.ThrowQueryException()
       at NHibernate.Hql.Ast.ANTLR.HqlSqlTranslator.Translate()
       at NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.Analyze(String collectionRole)
       at NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.DoCompile(IDictionary`2 replacements, Boolean shallow, String collectionRole)
       at NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.Compile(IDictionary`2 replacements, Boolean shallow)
       at NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(IASTNode ast, String queryIdentifier, String collectionRole, Boolean shallow, IDictionary`2 filters, ISessionFactoryImplementor factory)
       at NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(String queryIdentifier, IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary`2 filters, ISessionFactoryImplementor factory)
       at NHibernate.Engine.Query.HQLExpressionQueryPlan.CreateTranslators(String expressionStr, IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory)
       at NHibernate.Engine.Query.HQLExpressionQueryPlan..ctor(String expressionStr, IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory)
       at NHibernate.Engine.Query.HQLExpressionQueryPlan..ctor(String expressionStr, IQueryExpression queryExpression, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory)
       at NHibernate.Engine.Query.QueryPlanCache.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow, IDictionary`2 enabledFilters)
       at NHibernate.Impl.AbstractSessionImpl.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow)
       at NHibernate.Impl.AbstractSessionImpl.CreateQuery(IQueryExpression queryExpression)
       at NHibernate.Linq.DefaultQueryProvider.PrepareQuery(Expression expression, IQuery& query, NhLinqExpression& nhQuery)
       at NHibernate.Linq.DefaultQueryProvider.Execute(Expression expression)
       at NHibernate.Linq.DefaultQueryProvider.Execute[TResult](Expression expression)
       at Remotion.Linq.QueryableBase`1.GetEnumerator()
       at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
       at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
       at KitchenPC.DB.DatabaseAdapter.LoadIngredientsForIndex() in c:\KitchenPC\DB\DatabaseAdapter.cs:line 172

What am I doing wrong?

Answer 1

I've translated the Linq query to an ICriteria (QueryOver<>) query, and this seems to work. However, the code is fairly messy. Or, awesome depending on what you're into.

Models.Ingredients ing = null;
int? count = null;
var popularity = QueryOver.Of<Models.RecipeIngredients>()
   .Where(p => p.Ingredient.IngredientId == ing.IngredientId)
   .ToRowCountQuery();

var ingredients = session.QueryOver<Models.Ingredients>(() => ing)
   .SelectList(list => list
      .Select(p => p.IngredientId)
      .Select(p => p.DisplayName)
      .SelectSubQuery(popularity).WithAlias(() => count)
   )
   .OrderByAlias(() => count).Desc()
   .ThenBy(p => p.DisplayName).Asc()
   .List<Object[]>()
   .Select(i => new IngredientSource((Guid)i[0], (String)i[1]));

This produces a very similar query to the original:

SELECT
   this_.IngredientId as y0_,
   this_.DisplayName as y1_,
   (SELECT count(*) as y0_ FROM recipeingredients this_0_ WHERE this_0_.IngredientId = this_.IngredientId) as y2_
FROM ingredients this_
ORDER BY y2_ desc, this_.DisplayName asc