Max and Average evaluated locally

Here is my query

var stats = (from team in context.Teams
                   let teamCount = context.Teams.Count()
                   let roundTeamCount = context.RoundTeams.Count(rt => rt.RoundId == roundId)
                   let averagePoint = context.Teams.Select(p => p.Point).Average()
                   let maxPoint = context.Teams.Max(t => t.Point)
                       select new { averagePoint, maxPoint, teamCount, roundTeamCount }
            ) .FirstOrDefault();

 public class Team
{
       public int Id{ get; set; }

      public string Name { get; set; }

        public int Point { get; set; }
}

public class RoundTeamPlayer 
{
    public int Id{ get; set; }

    public int Point { get; set; }

    public long RoundId { get; set; }

    public Round Round { get; set; }

    public long TeamId { get; set; }

    public Team Team { get; set; }
}

After running query VS hangs for several seconds and get these messages:

Microsoft Visual Studio
---------------------------
Evaluating the function '<>f__AnonymousType35<<averagePoint>j__TPar, <maxPoint>j__TPar, <teamCount>j__TPar, <roundTeamCount>j__TPar>.averagePoint.get' timed out and needed to be aborted in an unsafe way. This may have corrupted the target process.

If the problem happens regularly, consider disabling the Tools->Options setting "Debugging->General->Enable property evaluation and other implicit function calls" or change the code to disable evaluation of this method. See help for information on doing this.

warn: Microsoft.EntityFrameworkCore.Query[20500]
      The LINQ expression 'Average()' could not be translated and will be evaluated locally.
warn: Microsoft.EntityFrameworkCore.Query[20502]
      Possible unintended use of a potentially throwing aggregate method (Min, Max, Average) in a subquery. Client evaluation will be used and operator will throw if no data exists. Changing the subquery result type to a nullable type will allow full translation.
warn: Microsoft.EntityFrameworkCore.Query[20500]
      The LINQ expression 'Max()' could not be translated and will be evaluated locally.

Translated sql queries:

Microsoft.EntityFrameworkCore.Database.Command:Information: Executed DbCommand (51ms) [Parameters=[@__8__locals1_roundId_0='?'], CommandType='Text', CommandTimeout='30']
SELECT TOP(1) (
    SELECT COUNT(*)
    FROM [Teams] AS [t2]
) AS [teamCount], (
    SELECT COUNT(*)
    FROM [RoundTeams] AS [rt]
    WHERE [rt].[RoundId] = @__8__locals1_roundId_0
) AS [roundTeamCount]

FROM [Teams] AS [team]
Microsoft.EntityFrameworkCore.Database.Command:Information: Executed DbCommand (39ms) [Parameters=[], CommandType='Text', CommandTimeout='30']

SELECT AVG(CAST([p1].[Point] AS float))
FROM [Teams] AS [p1]

Microsoft.EntityFrameworkCore.Database.Command:Information: Executed DbCommand (32ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT MAX([t1].[Point])
FROM [Teams] AS [t1]

When I use FirstOrDefaultAsync() there no VS hangs but still get The LINQ expression 'Average()' ... warns

[smitpatel]

@mo-esmp - While having a check, removes need for throwing behavior, it is pretty difficult pattern to recognize in code (rather than human-read), so EF Core does not account for it and still goes for throwing behavior causing client eval.

Putting a cast outside of the aggregate operator has no effect. You are still computing result over non-nullable type and saving it into nullable property. You need to introduce cast inside the operator. e.g. let maxPoint = context.Teams.Max(t => (int?)t.Point)

[mo-esmp]

@smitpatel I changed the query and I checked for null scenario but still same thing is happening. so the only way is changingPoint property to nullable int ?

var stats = (from team in context.Teams
                 let teamCount = context.Teams.Count()
                 let roundTeamCount = context.RoundTeams.Count(rt => rt.RoundId == roundId)
                 let averagePoint = context.Teams.Count() == 0 ? null : (double?)context.Teams.Select(p => p.Point).Average()
                 let maxPoint = context.Teams.Count() == 0 ? null : (int?)context.Teams.Max(t => t.Point)
                 select new { averagePoint, maxPoint, teamCount, roundTeamCount })
            .FirstOrDefault();