Add Std Dev and Variance using EF.Functions

src/EFCore.Jet/Extensions/JetServiceCollectionExtensions.cs

@@ -59,6 +59,7 @@ public static IServiceCollection AddEntityFrameworkJet([NotNull] this IServiceCo
                 .TryAdd<ISingletonOptions, IJetOptions>(p => p.GetRequiredService<IJetOptions>())
                 .TryAdd<IQueryCompilationContextFactory, JetQueryCompilationContextFactory>()
                 .TryAdd<IMethodCallTranslatorProvider, JetMethodCallTranslatorProvider>()
+                .TryAdd<IAggregateMethodCallTranslatorProvider, JetAggregateMethodCallTranslatorProvider>()
                 .TryAdd<IMemberTranslatorProvider, JetMemberTranslatorProvider>()
                 .TryAdd<IQuerySqlGeneratorFactory, JetQuerySqlGeneratorFactory>()
                 .TryAdd<IRelationalSqlTranslatingExpressionVisitorFactory, JetSqlTranslatingExpressionVisitorFactory>()

src/EFCore.Jet/Query/ExpressionTranslators/Internal/JetAggregateMethodCallTranslatorProvider.cs

@@ -0,0 +1,30 @@
+using Microsoft.EntityFrameworkCore.Query;
+
+namespace EntityFrameworkCore.Jet.Query.ExpressionTranslators.Internal;
+
+/// <summary>
+///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+///     any release. You should only use it directly in your code with extreme caution and knowing that
+///     doing so can result in application failures when updating to a new Entity Framework Core release.
+/// </summary>
+public class JetAggregateMethodCallTranslatorProvider : RelationalAggregateMethodCallTranslatorProvider
+{
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    public JetAggregateMethodCallTranslatorProvider(RelationalAggregateMethodCallTranslatorProviderDependencies dependencies)
+        : base(dependencies)
+    {
+        var sqlExpressionFactory = dependencies.SqlExpressionFactory;
+        var typeMappingSource = dependencies.RelationalTypeMappingSource;
+
+        AddTranslators(
+        [
+            new JetStatisticsAggregateMethodTranslator(sqlExpressionFactory, typeMappingSource)
+        ]);
+    }
+}

src/EFCore.Jet/Query/ExpressionTranslators/Internal/JetMethodCallTranslatorProvider.cs

@@ -16,7 +16,7 @@ public class JetMethodCallTranslatorProvider : RelationalMethodCallTranslatorPro
         ///     directly from your code. This API may change or be removed in future releases.
         /// </summary>
         public JetMethodCallTranslatorProvider(
-            [NotNull] RelationalMethodCallTranslatorProviderDependencies dependencies)
+            RelationalMethodCallTranslatorProviderDependencies dependencies)
             : base(dependencies)
         {
             var sqlExpressionFactory = (JetSqlExpressionFactory)dependencies.SqlExpressionFactory;

src/EFCore.Jet/Query/ExpressionTranslators/Internal/JetStatisticsAggregateMethodTranslator.cs

@@ -0,0 +1,72 @@
+using System.Collections.Generic;
+using System.Reflection;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+using Microsoft.EntityFrameworkCore.Query;
+using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
+using Microsoft.EntityFrameworkCore.Storage;
+
+namespace EntityFrameworkCore.Jet.Query.ExpressionTranslators.Internal;
+
+/// <summary>
+///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+///     any release. You should only use it directly in your code with extreme caution and knowing that
+///     doing so can result in application failures when updating to a new Entity Framework Core release.
+/// </summary>
+public class JetStatisticsAggregateMethodTranslator : IAggregateMethodCallTranslator
+{
+    private readonly ISqlExpressionFactory _sqlExpressionFactory;
+    private readonly RelationalTypeMapping _doubleTypeMapping;
+
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    public JetStatisticsAggregateMethodTranslator(
+        ISqlExpressionFactory sqlExpressionFactory,
+        IRelationalTypeMappingSource typeMappingSource)
+    {
+        _sqlExpressionFactory = sqlExpressionFactory;
+        _doubleTypeMapping = typeMappingSource.FindMapping(typeof(double))!;
+    }
+
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    public virtual SqlExpression? Translate(
+        MethodInfo method,
+        EnumerableExpression source,
+        IReadOnlyList<SqlExpression> arguments,
+        IDiagnosticsLogger<DbLoggerCategory.Query> logger)
+    {
+        // Docs: https://docs.microsoft.com/sql/t-sql/functions/aggregate-functions-transact-sql
+
+        if (method.DeclaringType != typeof(JetDbFunctionsExtensions)
+            || source.Selector is not SqlExpression sqlExpression)
+        {
+            return null;
+        }
+
+        var functionName = method.Name switch
+        {
+            nameof(JetDbFunctionsExtensions.StandardDeviationSample) => "StDev",
+            nameof(JetDbFunctionsExtensions.StandardDeviationPopulation) => "StDevP",
+            nameof(JetDbFunctionsExtensions.VarianceSample) => "Var",
+            nameof(JetDbFunctionsExtensions.VariancePopulation) => "VarP",
+            _ => null
+        };
+
+        if (functionName is null)
+        {
+            return null;
+        }
+
+        return _sqlExpressionFactory.Function(functionName, [sqlExpression], nullable: true, argumentsPropagateNullability: [false], typeof(double), _doubleTypeMapping);
+    }
+}

test/EFCore.Jet.FunctionalTests/GreenTests/ace_2010_odbc_x86.txt

@@ -13060,6 +13060,8 @@ EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Sel
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Select_mathf_truncate(async: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Select_ToString_IndexOf(async: False)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Select_ToString_IndexOf(async: True)
+EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.StandardDeviation(async: False)
+EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.StandardDeviation(async: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Static_equals_int_compared_to_long(isAsync: False)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Static_equals_int_compared_to_long(isAsync: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Static_equals_nullable_datetime_compared_to_non_nullable(isAsync: False)
@@ -13194,6 +13196,8 @@ EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Tri
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.TrimEnd_without_arguments_in_predicate(isAsync: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.TrimStart_without_arguments_in_predicate(isAsync: False)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.TrimStart_without_arguments_in_predicate(isAsync: True)
+EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Variance(async: False)
+EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Variance(async: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Where_DateOnly_FromDateTime(async: False)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Where_DateOnly_FromDateTime(async: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Where_functions_nested(isAsync: False)

test/EFCore.Jet.FunctionalTests/GreenTests/ace_2010_oledb_x86.txt

@@ -14350,6 +14350,8 @@ EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Sel
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Select_mathf_truncate(async: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Select_ToString_IndexOf(async: False)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Select_ToString_IndexOf(async: True)
+EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.StandardDeviation(async: False)
+EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.StandardDeviation(async: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Static_equals_int_compared_to_long(isAsync: False)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Static_equals_int_compared_to_long(isAsync: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Static_equals_nullable_datetime_compared_to_non_nullable(isAsync: False)
@@ -14484,6 +14486,8 @@ EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Tri
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.TrimEnd_without_arguments_in_predicate(isAsync: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.TrimStart_without_arguments_in_predicate(isAsync: False)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.TrimStart_without_arguments_in_predicate(isAsync: True)
+EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Variance(async: False)
+EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Variance(async: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Where_DateOnly_FromDateTime(async: False)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Where_DateOnly_FromDateTime(async: True)
 EntityFrameworkCore.Jet.FunctionalTests.Query.NorthwindFunctionsQueryJetTest.Where_functions_nested(isAsync: False)