Wrong distance values with GroupBy

[vfichot]

The following query with GroupBy gives wrong results for distance (Geography)

 var point = Utilities.CreatePoint(-1.209424, 44.599878);

BugDistance.zip

var query = from table1 in context.Table1
                   select new
                   {
                          Code = table1.Code,
                           Distance = table1.Location.Distance(point)
                   };

var value = query.First();

// OK : 543758 m
Console.WriteLine($"Code {value.Code}, Distance: {value.Distance}");

var value2 = query.GroupBy(p => p.Code).Select(grp => grp.First()).First();

// KO ; 5.51 ?????

BugDistance.zip

 Console.WriteLine($"Code {value2.Code}, Distance: {value2.Distance}");

Further technical details

EF Core version: 2.2.6
Database Provider: Microsoft.EntityFrameworkCore.SqlServer
Database: SQL Server Express 2014 SP3
Operating system: 8.1
IDE: Visual Studio 2017 15.9.14

[ajcvickers]

Note for triage: client-eval of the GrioupBy query.

dbug: Microsoft.EntityFrameworkCore.Query[10101]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      Compiling query model:
      '(from IGrouping<string, <>f__AnonymousType1<string, double>> grp in
          (from Table1 table1 in DbSet<Table1>
          select new {
              [table1].Code,
              double [table1].Location.Distance(__point_0)
           }).GroupBy([table1].Code, new {
                  [table1].Code,
                  double [table1].Location.Distance(__point_0)
               })
      select
          (from <>f__AnonymousType1<string, double> <generated>_1 in [grp]
          select [<generated>_1]).First()).First()'
warn: Microsoft.EntityFrameworkCore.Query[10103]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      Query: '(from <>f__AnonymousType1<string, double> <generated>_1 in [grp] select [<generated>_1]).First()' uses First/FirstOrDefault/Last/LastOrDefault operation without OrderBy and filter which may lead to unpredictable results.
warn: Microsoft.EntityFrameworkCore.Query[10103]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      Query: '(from IGrouping<string, <>f__AnonymousType1<string, double>> grp in  (from Table1 table1 in DbSet<Ta...' uses First/FirstOrDefault/Last/LastOrDefault operation without OrderBy and filter which may lead to unpredictable results.
dbug: Microsoft.EntityFrameworkCore.Query[10104]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      Optimized query model:
      '(from IGrouping<string, <>f__AnonymousType1<string, double>> grp in
          (from Table1 table1 in DbSet<Table1>
          select new {
              [table1].Code,
              double [table1].Location.Distance(__point_0)
           }).GroupBy([table1].Code, new {
                  [table1].Code,
                  double [table1].Location.Distance(__point_0)
               })
      select
          (from <>f__AnonymousType1<string, double> <generated>_1 in [grp]
          select [<generated>_1]).First()).First()'
warn: Microsoft.EntityFrameworkCore.Query[20500]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      The LINQ expression 'GroupBy([table1].Code, new <>f__AnonymousType1`2(Code = [table1].Code, Distance = [table1].Location.Distance(__point_0)))' could not be translated and will be evaluated locally.
warn: Microsoft.EntityFrameworkCore.Query[20500]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      The LINQ expression 'First()' could not be translated and will be evaluated locally.
warn: Microsoft.EntityFrameworkCore.Query[20500]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      The LINQ expression 'First()' could not be translated and will be evaluated locally.
warn: Microsoft.EntityFrameworkCore.Query[20500]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      The LINQ expression 'First()' could not be translated and will be evaluated locally.
dbug: Microsoft.EntityFrameworkCore.Query[10107]
      => Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor
      (QueryContext queryContext) => IEnumerable<<>f__AnonymousType1<string, double>> _InterceptExceptions(
      |__ source: IEnumerable<<>f__AnonymousType1<string, double>> _ToSequence(() => <>f__AnonymousType1<string, double> First(IEnumerable<<>f__AnonymousType1<string, double>> _Select(
      |   |__ source: IEnumerable<IGrouping<string, <>f__AnonymousType1<string, double>>> _GroupBy(
      |   |   |__ source: IEnumerable<ValueBuffer> _ShapedQuery(
      |   |   |   |__ queryContext: queryContext,
      |   |   |   |__ shaperCommandContext: SelectExpression:
      |   |   |   |       SELECT [table1].[Code], [table1].[Location].STDistance(@__point_0) AS [Distance], [table1].[Location]
      |   |   |   |       FROM [Table1] AS [table1]
      |   |   |   |       ORDER BY [table1].[Code],
      |   |   |   |__ shaper: ValueBufferShaper),
      |   |   |__ keySelector: (ValueBuffer table1) => string TryReadValue(table1, 0, Table1.Code),
      |   |   |__ elementSelector: (ValueBuffer table1) => new {
      |   |           string TryReadValue(table1, 0, Table1.Code),
      |   |           double IGeometry TryReadValue(table1, 2, Table1.Location).Distance(IPoint GetParameterValue(
      |   |           |__ queryContext: queryContext,
      |   |           |__ parameterName: "__point_0"))
      |   |        }),
      |   |__ selector: (IGrouping<string, <>f__AnonymousType1<string, double>> grp) => <>f__AnonymousType1<string, double> First(grp)))),
      |__ contextType: BugDistance.Models.TestStoreContext,
      |__ logger: DiagnosticsLogger<Query>,
      |__ queryContext: queryContext)
dbug: Microsoft.EntityFrameworkCore.Database.Connection[20000]
      Opening connection to database 'TestStore' on server '.\SQlEXPRESS'.
dbug: Microsoft.EntityFrameworkCore.Database.Connection[20001]
      Opened connection to database 'TestStore' on server '.\SQlEXPRESS'.
dbug: Microsoft.EntityFrameworkCore.Database.Command[20100]
      Executing DbCommand [Parameters=[@__point_0='?' (Size = 22) (DbType = Binary)], CommandType='Text', CommandTimeout='30']
      SELECT [table1].[Code], [table1].[Location].STDistance(@__point_0) AS [Distance], [table1].[Location]
      FROM [Table1] AS [table1]
      ORDER BY [table1].[Code]

[smitpatel]

Duplicate of #12088