Max with 0 result give error Sequence contains no elements when using .Max() or .MaxAsync()

When the result of max is 0 a error message is generated

Steps to reproduce

_ctx.ChapterQuestions.Where(x => x.SurveyChapterId == surveyChapterId).Max(x => x.SequenceNumber+0) // produce error

_ctx.ChapterQuestions.Where(x => x.SurveyChapterId == surveyChapterId).Max(x => x.SequenceNumber+1) // is allowed

sql data

SELECT id,SequenceNumber FROM [ChapterQuestions] AS [c] WHERE [c].[SurveyChapterId] = 702
---
Id	SequenceNumber	
2293	0	

stack trace

dbug: Microsoft.EntityFrameworkCore.Query[10107]
      (queryContext) => Single<int>(new QueryingEnumerable<int>(
          (RelationalQueryContext)queryContext,
          SqlServerQuerySqlGeneratorFactory,
          SqlExpressionFactory,
          ParameterNameGeneratorFactory,
          Projection Mapping:
              EmptyProjectionMember -> 0
          SELECT MAX(c.SequenceNumber + 0)
          FROM ChapterQuestions AS c
          WHERE (c.SurveyChapterId == @__surveyChapterId_0) && NotEqual(@__surveyChapterId_0),
          Func<QueryContext, DbDataReader, ResultContext, int[], ResultCoordinator, int>,
          Survey.Entities.Context.SurveyContext,
          DiagnosticsLogger<Query>
      ))
dbug: Microsoft.EntityFrameworkCore.Database.Command[20103]
      Creating DbCommand for 'ExecuteReader'.
dbug: Microsoft.EntityFrameworkCore.Database.Command[20104]
      Created DbCommand for 'ExecuteReader' (0ms).
dbug: Microsoft.EntityFrameworkCore.Database.Connection[20000]
      Opening connection to database 'survey' on server '(localdb)\mssqllocaldb'.
dbug: Microsoft.EntityFrameworkCore.Database.Connection[20001]
      Opened connection to database 'survey' on server '(localdb)\mssqllocaldb'.
info: Microsoft.EntityFrameworkCore.Database.Command[20100]
      Executing DbCommand [Parameters=[@__surveyChapterId_0='702'], CommandType='Text', CommandTimeout='30']
      SELECT MAX([c].[SequenceNumber] + 0)
      FROM [ChapterQuestions] AS [c]
      WHERE ([c].[SurveyChapterId] = @__surveyChapterId_0) AND @__surveyChapterId_0 IS NOT NULL
dbug: Microsoft.EntityFrameworkCore.Database.Command[20101]
      Executed DbCommand (3ms) [Parameters=[@__surveyChapterId_0='702'], CommandType='Text', CommandTimeout='30']
      SELECT MAX([c].[SequenceNumber] + 0)
      FROM [ChapterQuestions] AS [c]
      WHERE ([c].[SurveyChapterId] = @__surveyChapterId_0) AND @__surveyChapterId_0 IS NOT NULL
fail: Microsoft.EntityFrameworkCore.Query[10100]
      An exception occurred while iterating over the results of a query for context type 'Survey.Entities.Context.SurveyContext'.
      System.InvalidOperationException: Sequence contains no elements.
         at lambda_method(Closure , QueryContext , DbDataReader , ResultContext , Int32[] , ResultCoordinator )
         at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.QueryingEnumerable`1.Enumerator.MoveNext()
System.InvalidOperationException: Sequence contains no elements.
   at lambda_method(Closure , QueryContext , DbDataReader , ResultContext , Int32[] , ResultCoordinator )
   at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.QueryingEnumerable`1.Enumerator.MoveNext()
dbug: Microsoft.EntityFrameworkCore.Database.Command[20300]
      A data reader was disposed.
dbug: Microsoft.EntityFrameworkCore.Database.Connection[20002]
      Closing connection to database 'survey' on server '(localdb)\mssqllocaldb'.
dbug: Microsoft.EntityFrameworkCore.Database.Connection[20003]
      Closed connection to database 'survey' on server '(localdb)\mssqllocaldb'.
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action Survey.WebApi.Survey.ManageSurveys.Controllers.SurveyManagementController.InsertChapterQuestion (Survey.WebApi) in 39.4262ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'Survey.WebApi.Survey.ManageSurveys.Controllers.SurveyManagementController.InsertChapterQuestion (Survey.WebApi)'
fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1]
      An unhandled exception has occurred while executing the request.
System.InvalidOperationException: Sequence contains no elements.
   at lambda_method(Closure , QueryContext , DbDataReader , ResultContext , Int32[] , ResultCoordinator )
   at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.QueryingEnumerable`1.Enumerator.MoveNext()
   at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression)
   at System.Linq.Queryable.Max[TSource,TResult](IQueryable`1 source, Expression`1 selector)
   at Survey.WebApi.Survey.ManageSurveys.DbServices.ManageSurveyQuestionProvider.InsertChapterQuestion(Int32 surveyId, Int32 surveyChapterId, Int32 questionId) in C:\git\mijnzorgpeiler\Survey\Survey.WebApi\Survey\ManageSurveys\DbServices\ManageSurveyQuestionProvider.cs:line 50
   at Survey.WebApi.Survey.ManageSurveys.Services.ManageSurveyService.InsertChapterQuestion(Int32 surveyId, Int32 surveyChapterId, Int32 questionId) in C:\git\mijnzorgpeiler\Survey\Survey.WebApi\Survey\ManageSurveys\Services\ManageSurveyService.cs:line 69
   at Survey.WebApi.Survey.ManageSurveys.Controllers.SurveyManagementController.InsertChapterQuestion(Int32 surveyId, Int32 surveyChapterId, Int32 questionId) in C:\git\mijnzorgpeiler\Survey\Survey.WebApi\Survey\ManageSurveys\Controllers\SurveyManagementController.cs:line 59
   at lambda_method(Closure , Object )
   at Microsoft.Extensions.Internal.ObjectMethodExecutorAwaitable.Awaiter.GetResult()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()

Further technical details

EF Core version: Database provider: (e.g. Microsoft.EntityFrameworkCore.SqlServer) Target framework: (e.g. .NET Core 3.1) Operating system: IDE: (e.g. Visual Studio 2019 16.4)

[myesn]

May I ask when version 3.1.1 can be released, I also encountered the same problem.

I found the weekly status updates link

[roji]

@Pyrdacor we have various cases where we don’t match the .NET behavior - a good example is string equality, which on some databases is case-insensitive whereas it’s case-sensitive in .NET. The team was unanimous that there’s more danger in mimicking the (problematic) .NET behavior (data corruption) than there is in the current behavior.

As to this being understandable or not, that’s quite subjective - it seems pretty clear to me that Max is saying it has no values. In any case, better an exception that the user can investigate in understand, than silent bad data because of an implicit conversion from null string to zero.