Implement sum and average over TimeSpan (#2423)

Closes #2339

src/EFCore.PG.NodaTime/Extensions/NpgsqlNodaTimeDbFunctionsExtensions.cs

+// ReSharper disable once CheckNamespace
+namespace Microsoft.EntityFrameworkCore;
+
+/// <summary>
+/// Provides extension methods supporting NodaTime function translation for PostgreSQL.
+/// </summary>
+public static class NpgsqlNodaTimeDbFunctionsExtensions
+{
+    /// <summary>
+    /// Computes the sum of the non-null input intervals. Corresponds to the PostgreSQL <c>sum</c> aggregate function.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="input">The input values to be summed.</param>
+    /// <seealso href="https://www.postgresql.org/docs/current/functions-aggregate.html">PostgreSQL documentation for aggregate functions.</seealso>
+    public static Period? Sum(this DbFunctions _, IEnumerable<Period> input)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(Sum)));
+
+    /// <summary>
+    /// Computes the sum of the non-null input intervals. Corresponds to the PostgreSQL <c>sum</c> aggregate function.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="input">The input values to be summed.</param>
+    /// <seealso href="https://www.postgresql.org/docs/current/functions-aggregate.html">PostgreSQL documentation for aggregate functions.</seealso>
+    public static Duration? Sum(this DbFunctions _, IEnumerable<Duration> input)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(Sum)));
+
+    /// <summary>
+    /// Computes the average (arithmetic mean) of the non-null input intervals. Corresponds to the PostgreSQL <c>avg</c> aggregate function.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="input">The input values to be computed into an average.</param>
+    /// <seealso href="https://www.postgresql.org/docs/current/functions-aggregate.html">PostgreSQL documentation for aggregate functions.</seealso>
+    public static Period? Average(this DbFunctions _, IEnumerable<Period> input)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(Average)));
+
+    /// <summary>
+    /// Computes the average (arithmetic mean) of the non-null input intervals. Corresponds to the PostgreSQL <c>avg</c> aggregate function.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="input">The input values to be computed into an average.</param>
+    /// <seealso href="https://www.postgresql.org/docs/current/functions-aggregate.html">PostgreSQL documentation for aggregate functions.</seealso>
+    public static Duration? Average(this DbFunctions _, IEnumerable<Duration> input)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(Average)));
+}

src/EFCore.PG.NodaTime/Extensions/NpgsqlNodaTimeServiceCollectionExtensions.cs

@@ -22,6 +22,7 @@ public static class NpgsqlNodaTimeServiceCollectionExtensions
         new EntityFrameworkRelationalServicesBuilder(serviceCollection)
             .TryAdd<IRelationalTypeMappingSourcePlugin, NpgsqlNodaTimeTypeMappingSourcePlugin>()
             .TryAdd<IMethodCallTranslatorPlugin, NpgsqlNodaTimeMethodCallTranslatorPlugin>()
+            .TryAdd<IAggregateMethodCallTranslatorPlugin, NpgsqlNodaTimeAggregateMethodCallTranslatorPlugin>()
             .TryAdd<IMemberTranslatorPlugin, NpgsqlNodaTimeMemberTranslatorPlugin>()
             .TryAdd<IEvaluatableExpressionFilterPlugin, NpgsqlNodaTimeEvaluatableExpressionFilterPlugin>();
 

src/EFCore.PG.NodaTime/Query/Internal/NpgsqlNodaTimeAggregateMethodCallTranslatorPlugin.cs

+using Npgsql.EntityFrameworkCore.PostgreSQL.Query;
+
+namespace Npgsql.EntityFrameworkCore.PostgreSQL.NodaTime.Query.Internal;
+
+public class NpgsqlNodaTimeAggregateMethodCallTranslatorPlugin : IAggregateMethodCallTranslatorPlugin
+{
+    public NpgsqlNodaTimeAggregateMethodCallTranslatorPlugin(ISqlExpressionFactory sqlExpressionFactory)
+    {
+        if (sqlExpressionFactory is not NpgsqlSqlExpressionFactory npgsqlSqlExpressionFactory)
+        {
+            throw new ArgumentException($"Must be an {nameof(NpgsqlSqlExpressionFactory)}", nameof(sqlExpressionFactory));
+        }
+
+        Translators = new IAggregateMethodCallTranslator[]
+        {
+            new NpgsqlNodaTimeAggregateMethodTranslator(npgsqlSqlExpressionFactory)
+        };
+    }
+
+    public virtual IEnumerable<IAggregateMethodCallTranslator> Translators { get; }
+}
+
+public class NpgsqlNodaTimeAggregateMethodTranslator : IAggregateMethodCallTranslator
+{
+    private static readonly bool[][] FalseArrays = { Array.Empty<bool>(), new[] { false } };
+
+    private readonly NpgsqlSqlExpressionFactory _sqlExpressionFactory;
+
+    public NpgsqlNodaTimeAggregateMethodTranslator(NpgsqlSqlExpressionFactory sqlExpressionFactory)
+        => _sqlExpressionFactory = sqlExpressionFactory;
+
+    public virtual SqlExpression? Translate(
+        MethodInfo method,
+        EnumerableExpression source,
+        IReadOnlyList<SqlExpression> arguments,
+        IDiagnosticsLogger<DbLoggerCategory.Query> logger)
+    {
+        if (source.Selector is not SqlExpression sqlExpression || method.DeclaringType != typeof(NpgsqlNodaTimeDbFunctionsExtensions))
+        {
+            return null;
+        }
+
+        switch (method.Name)
+        {
+            case nameof(NpgsqlNodaTimeDbFunctionsExtensions.Sum):
+                return _sqlExpressionFactory.AggregateFunction(
+                    "sum",
+                    new[] { sqlExpression },
+                    source,
+                    nullable: true,
+                    argumentsPropagateNullability: FalseArrays[1],
+                    returnType: sqlExpression.Type,
+                    sqlExpression.TypeMapping);
+
+            case nameof(NpgsqlNodaTimeDbFunctionsExtensions.Average):
+                return _sqlExpressionFactory.AggregateFunction(
+                    "avg",
+                    new[] { sqlExpression },
+                    source,
+                    nullable: true,
+                    argumentsPropagateNullability: FalseArrays[1],
+                    returnType: sqlExpression.Type,
+                    sqlExpression.TypeMapping);
+
+            default:
+                return null;
+        }
+    }
+}

src/EFCore.PG/Extensions/DbFunctionsExtensions/NpgsqlAggregateDbFunctionsExtensions.cs

@@ -36,6 +36,24 @@ public static T[] JsonAgg<T>(this DbFunctions _, IEnumerable<T> input)
     public static T[] JsonbAgg<T>(this DbFunctions _, IEnumerable<T> input)
         => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(JsonbAgg)));
 
+    /// <summary>
+    /// Computes the sum of the non-null input intervals. Corresponds to the PostgreSQL <c>sum</c> aggregate function.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="input">The input values to be summed.</param>
+    /// <seealso href="https://www.postgresql.org/docs/current/functions-aggregate.html">PostgreSQL documentation for aggregate functions.</seealso>
+    public static TimeSpan? Sum(this DbFunctions _, IEnumerable<TimeSpan> input)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(Sum)));
+
+    /// <summary>
+    /// Computes the average (arithmetic mean) of the non-null input intervals. Corresponds to the PostgreSQL <c>avg</c> aggregate function.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="input">The input values to be computed into an average.</param>
+    /// <seealso href="https://www.postgresql.org/docs/current/functions-aggregate.html">PostgreSQL documentation for aggregate functions.</seealso>
+    public static TimeSpan? Average(this DbFunctions _, IEnumerable<TimeSpan> input)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(Average)));
+
     #region Range
 
     /// <summary>

src/EFCore.PG/Query/ExpressionTranslators/Internal/NpgsqlMiscAggregateMethodTranslator.cs

@@ -128,6 +128,26 @@ public class NpgsqlMiscAggregateMethodTranslator : IAggregateMethodCallTranslato
                         returnType: sqlExpression.Type,
                         sqlExpression.TypeMapping);
 
+                case nameof(NpgsqlAggregateDbFunctionsExtensions.Sum):
+                    return _sqlExpressionFactory.AggregateFunction(
+                        "sum",
+                        new[] { sqlExpression },
+                        source,
+                        nullable: true,
+                        argumentsPropagateNullability: FalseArrays[1],
+                        returnType: sqlExpression.Type,
+                        sqlExpression.TypeMapping);
+
+                case nameof(NpgsqlAggregateDbFunctionsExtensions.Average):
+                    return _sqlExpressionFactory.AggregateFunction(
+                        "avg",
+                        new[] { sqlExpression },
+                        source,
+                        nullable: true,
+                        argumentsPropagateNullability: FalseArrays[1],
+                        returnType: sqlExpression.Type,
+                        sqlExpression.TypeMapping);
+
                 case nameof(NpgsqlAggregateDbFunctionsExtensions.JsonbObjectAgg):
                 case nameof(NpgsqlAggregateDbFunctionsExtensions.JsonObjectAgg):
                     var isJsonb = method.Name == nameof(NpgsqlAggregateDbFunctionsExtensions.JsonbObjectAgg);

src/EFCore.PG/Query/Internal/NpgsqlSqlNullabilityProcessor.cs

@@ -199,6 +199,15 @@ PostgresUnknownBinaryExpression postgresUnknownBinaryExpression
             && visitedBase is SqlFunctionExpression { Name: "COALESCE", Arguments: { } } coalesceExpression
             && coalesceExpression.Arguments[0] is PostgresFunctionExpression wrappedFunctionExpression)
         {
+            // The base logic assumes sum is operating over numbers, which breaks sum over PG interval.
+            // Detect that case and remove the coalesce entirely (note that we don't need coalescing since sum function is in
+            // EF.Functions.Sum, and returns nullable. This is a temporary hack until #38158 is fixed.
+            if (sqlFunctionExpression.Type == typeof(TimeSpan)
+                || sqlFunctionExpression.Type.FullName is "NodaTime.Period" or "NodaTime.Duration")
+            {
+                return coalesceExpression.Arguments[0];
+            }
+
             var visitedArguments = coalesceExpression.Arguments!.ToArray();
             visitedArguments[0] = VisitPostgresFunctionComponents(wrappedFunctionExpression);
 

test/EFCore.PG.FunctionalTests/Query/GearsOfWarQueryNpgsqlTest.cs

@@ -346,6 +346,44 @@ public async Task Where_TimeSpan_TotalMilliseconds(bool async)
 WHERE (date_part('epoch', m.""Duration"") / 0.001) < 3700000.0");
     }
 
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public virtual async Task GroupBy_Property_Select_Sum_over_TimeSpan(bool async)
+    {
+        await AssertQueryScalar(
+            async,
+            ss => ss.Set<Mission>()
+                .GroupBy(o => o.Id)
+                .Select(g => EF.Functions.Sum(g.Select(o => o.Duration))),
+            ss => ss.Set<Mission>()
+                .GroupBy(o => o.Id)
+                .Select(g => (TimeSpan?)new TimeSpan(g.Sum(o => o.Duration.Ticks))));
+
+        AssertSql(
+            @"SELECT sum(m.""Duration"")
+FROM ""Missions"" AS m
+GROUP BY m.""Id""");
+    }
+
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public virtual async Task GroupBy_Property_Select_Average_over_TimeSpan(bool async)
+    {
+        await AssertQueryScalar(
+            async,
+            ss => ss.Set<Mission>()
+                .GroupBy(o => o.Id)
+                .Select(g => EF.Functions.Average(g.Select(o => o.Duration))),
+            ss => ss.Set<Mission>()
+                .GroupBy(o => o.Id)
+                .Select(g => (TimeSpan?)new TimeSpan((long)g.Average(o => o.Duration.Ticks))));
+
+        AssertSql(
+            @"SELECT avg(m.""Duration"")
+FROM ""Missions"" AS m
+GROUP BY m.""Id""");
+    }
+
     #endregion TimeSpan
 
     #region DateOnly

test/EFCore.PG.FunctionalTests/Query/NorthwindFunctionsQueryNpgsqlTest.cs

@@ -13,7 +13,7 @@ public class NorthwindFunctionsQueryNpgsqlTest : NorthwindFunctionsQueryRelation
         : base(fixture)
     {
         ClearLog();
-        Fixture.TestSqlLoggerFactory.SetTestOutputHelper(testOutputHelper);
+        //Fixture.TestSqlLoggerFactory.SetTestOutputHelper(testOutputHelper);
     }
 
     public override async Task IsNullOrWhiteSpace_in_predicate(bool async)

test/EFCore.PG.FunctionalTests/Query/NorthwindGroupByQueryNpgsqlTest.cs

@@ -3163,6 +3163,8 @@ into g
 GROUP BY o.""CustomerID""");
     }
 
+    // See aggregate tests over TimeSpan in GearsOfWarQueryNpsgqlTest
+
     private void AssertSql(params string[] expected)
         => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);
 

test/EFCore.PG.NodaTime.FunctionalTests/NodaTimeQueryNpgsqlTest.cs

@@ -755,6 +755,48 @@ public Task Period_FromTicks_is_not_translated()
             () => ctx.Set<NodaTimeTypes>().Where(t => Period.FromNanoseconds(t.Id).Seconds == 1).ToListAsync());
     }
 
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public async Task GroupBy_Property_Select_Sum_over_Period(bool async)
+    {
+        using var ctx = CreateContext();
+
+        // Note: Unlike Duration, Period can't be converted to total ticks (because its absolute time varies).
+        var query = ctx.Set<NodaTimeTypes>()
+            .GroupBy(o => o.Id)
+            .Select(g => EF.Functions.Sum(g.Select(o => o.Period)));
+
+        _ = async
+            ? await query.ToListAsync()
+            : query.ToList();
+
+        AssertSql(
+            @"SELECT sum(n.""Period"")
+FROM ""NodaTimeTypes"" AS n
+GROUP BY n.""Id""");
+    }
+
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public async Task GroupBy_Property_Select_Average_over_Period(bool async)
+    {
+        using var ctx = CreateContext();
+
+        // Note: Unlike Duration, Period can't be converted to total ticks (because its absolute time varies).
+        var query = ctx.Set<NodaTimeTypes>()
+            .GroupBy(o => o.Id)
+            .Select(g => EF.Functions.Average(g.Select(o => o.Period)));
+
+        _ = async
+            ? await query.ToListAsync()
+            : query.ToList();
+
+        AssertSql(
+            @"SELECT avg(n.""Period"")
+FROM ""NodaTimeTypes"" AS n
+GROUP BY n.""Id""");
+    }
+
     #endregion Period
 
     #region Duration
@@ -894,6 +936,44 @@ public async Task Duration_Seconds(bool async)
 WHERE floor(date_part('second', n.""Duration""))::int = 8");
     }
 
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public async Task GroupBy_Property_Select_Sum_over_Duration(bool async)
+    {
+        await AssertQueryScalar(
+            async,
+            ss => ss.Set<NodaTimeTypes>()
+                .GroupBy(o => o.Id)
+                .Select(g => EF.Functions.Sum(g.Select(o => o.Duration))),
+            expectedQuery: ss => ss.Set<NodaTimeTypes>()
+                .GroupBy(o => o.Id)
+                .Select(g => (Duration?)Duration.FromTicks(g.Sum(o => o.Duration.TotalTicks))));
+
+        AssertSql(
+            @"SELECT sum(n.""Duration"")
+FROM ""NodaTimeTypes"" AS n
+GROUP BY n.""Id""");
+    }
+
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public async Task GroupBy_Property_Select_Average_over_Duration(bool async)
+    {
+        await AssertQueryScalar(
+            async,
+            ss => ss.Set<NodaTimeTypes>()
+                .GroupBy(o => o.Id)
+                .Select(g => EF.Functions.Average(g.Select(o => o.Duration))),
+            expectedQuery: ss => ss.Set<NodaTimeTypes>()
+                .GroupBy(o => o.Id)
+                .Select(g => (Duration?)Duration.FromTicks((long)g.Average(o => o.Duration.TotalTicks))));
+
+        AssertSql(
+            @"SELECT avg(n.""Duration"")
+FROM ""NodaTimeTypes"" AS n
+GROUP BY n.""Id""");
+    }
+
     #endregion
 
     #region Interval