Translate DateTime.TimeOfDay and NodaTime LocalDateTime.Time (#2802)

Closes #2801

Author: roji

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

@@ -282,74 +282,42 @@ SqlExpression Upper()
     }
 
     private SqlExpression? TranslateDateTime(SqlExpression instance, MemberInfo member, Type returnType)
-    {
-        switch (member.Name)
+        => member.Name switch
         {
-            case "Year":
-            case "Years":
-                return GetDatePartExpression(instance, "year");
-
-            case "Month":
-            case "Months":
-                return GetDatePartExpression(instance, "month");
-
-            case "DayOfYear":
-                return GetDatePartExpression(instance, "doy");
-
-            case "Day":
-            case "Days":
-                return GetDatePartExpression(instance, "day");
-
-            case "Hour":
-            case "Hours":
-                return GetDatePartExpression(instance, "hour");
-
-            case "Minute":
-            case "Minutes":
-                return GetDatePartExpression(instance, "minute");
-
-            case "Second":
-            case "Seconds":
-                return GetDatePartExpression(instance, "second", true);
-
-            case "Millisecond":
-            case "Milliseconds":
-                return null; // Too annoying
-
-            case "DayOfWeek":
-                // Unlike DateTime.DayOfWeek, NodaTime's IsoDayOfWeek enum doesn't exactly correspond to PostgreSQL's
-                // values returned by date_part('dow', ...): in NodaTime Sunday is 7 and not 0, which is None.
-                // So we generate a CASE WHEN expression to translate PostgreSQL's 0 to 7.
-                var getValueExpression = GetDatePartExpression(instance, "dow", true);
-                // TODO: Can be simplified once https://github.com/aspnet/EntityFrameworkCore/pull/16726 is in
-                return
-                    _sqlExpressionFactory.Case(
-                        new[]
-                        {
-                            new CaseWhenClause(
-                                _sqlExpressionFactory.Equal(getValueExpression, _sqlExpressionFactory.Constant(0)),
-                                _sqlExpressionFactory.Constant(7))
-                        },
-                        getValueExpression
-                    );
+            "Year" or "Years" => GetDatePartExpression(instance, "year"),
+            "Month" or "Months" => GetDatePartExpression(instance, "month"),
+            "DayOfYear" => GetDatePartExpression(instance, "doy"),
+            "Day" or "Days" => GetDatePartExpression(instance, "day"),
+            "Hour" or "Hours" => GetDatePartExpression(instance, "hour"),
+            "Minute" or "Minutes" => GetDatePartExpression(instance, "minute"),
+            "Second" or "Seconds" => GetDatePartExpression(instance, "second", true),
+            "Millisecond" or "Milliseconds" => null, // Too annoying
+
+            // Unlike DateTime.DayOfWeek, NodaTime's IsoDayOfWeek enum doesn't exactly correspond to PostgreSQL's
+            // values returned by date_part('dow', ...): in NodaTime Sunday is 7 and not 0, which is None.
+            // So we generate a CASE WHEN expression to translate PostgreSQL's 0 to 7.
+            "DayOfWeek" when GetDatePartExpression(instance, "dow", true) is var getValueExpression
+                => _sqlExpressionFactory.Case(
+                    getValueExpression,
+                    new[]
+                    {
+                        new CaseWhenClause(_sqlExpressionFactory.Constant(0), _sqlExpressionFactory.Constant(7))
+                    },
+                    getValueExpression),
 
             // PG allows converting a timestamp directly to date, truncating the time; but given a timestamptz, it performs a time zone
             // conversion (based on TimeZone), which we don't want (so avoid translating except on timestamp).
             // The translation for ZonedDateTime.Date converts to timestamp before ending up here.
-            case "Date" when instance.TypeMapping is TimestampLocalDateTimeMapping or LegacyTimestampInstantMapping:
-                return _sqlExpressionFactory.Convert(instance, typeof(LocalDate), _typeMappingSource.FindMapping(typeof(LocalDate))!);
-
-            case "TimeOfDay":
-                // TODO: Technically possible simply via casting to PG time,
-                // but ExplicitCastExpression only allows casting to PG types that
-                // are default-mapped from CLR types (timespan maps to interval,
-                // which timestamp cannot be cast into)
-                return null;
-
-            default:
-                return null;
-        }
-    }
+            "Date" when instance.TypeMapping is TimestampLocalDateTimeMapping or LegacyTimestampInstantMapping
+                => _sqlExpressionFactory.Convert(instance, typeof(LocalDate), _typeMappingSource.FindMapping(typeof(LocalDate))!),
+
+            "TimeOfDay" => _sqlExpressionFactory.Convert(
+                instance,
+                typeof(LocalTime),
+                _typeMappingSource.FindMapping(typeof(LocalTime), storeTypeName: "time")),
+
+            _ => null
+        };
 
     /// <summary>
     /// Constructs the date_part expression.

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

@@ -12,6 +12,7 @@ namespace Npgsql.EntityFrameworkCore.PostgreSQL.Query.ExpressionTranslators.Inte
 /// </remarks>
 public class NpgsqlDateTimeMemberTranslator : IMemberTranslator
 {
+    private readonly IRelationalTypeMappingSource _typeMappingSource;
     private readonly NpgsqlSqlExpressionFactory _sqlExpressionFactory;
     private readonly RelationalTypeMapping _timestampMapping;
     private readonly RelationalTypeMapping _timestampTzMapping;
@@ -26,6 +27,7 @@ public NpgsqlDateTimeMemberTranslator(
         IRelationalTypeMappingSource typeMappingSource,
         NpgsqlSqlExpressionFactory sqlExpressionFactory)
     {
+        _typeMappingSource = typeMappingSource;
         _timestampMapping = typeMappingSource.FindMapping("timestamp without time zone")!;
         _timestampTzMapping = typeMappingSource.FindMapping("timestamp with time zone")!;
         _sqlExpressionFactory = sqlExpressionFactory;
@@ -128,11 +130,10 @@ public NpgsqlDateTimeMemberTranslator(
             // .NET's DayOfWeek is an enum, but its int values happen to correspond to PostgreSQL
             nameof(DateTime.DayOfWeek) => GetDatePartExpression(instance!, "dow", floor: true),
 
-            // TODO: Technically possible simply via casting to PG time, should be better in EF Core 3.0
-            // but ExplicitCastExpression only allows casting to PG types that
-            // are default-mapped from CLR types (timespan maps to interval,
-            // which timestamp cannot be cast into)
-            nameof(DateTime.TimeOfDay) => null,
+            nameof(DateTime.TimeOfDay) => _sqlExpressionFactory.Convert(
+                instance!,
+                typeof(TimeSpan),
+                _typeMappingSource.FindMapping(typeof(TimeSpan), storeTypeName: "time")),
 
             // TODO: Should be possible
             nameof(DateTime.Ticks) => null,

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

@@ -33,6 +33,17 @@ WHERE date_trunc('day', now()::timestamp) = date_trunc('day', now()::timestamp)
 """);
     }
 
+    public override async Task Time_of_day_datetime(bool async)
+    {
+        await base.Time_of_day_datetime(async);
+
+        AssertSql(
+"""
+SELECT o."OrderDate"::time
+FROM "Orders" AS o
+""");
+    }
+
     public override async Task Where_datetime_date_component(bool async)
     {
         await base.Where_datetime_date_component(async);

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

@@ -311,6 +311,23 @@ await AssertQuery(
 """);
     }
 
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public async Task LocalDateTime_Time(bool async)
+    {
+        await AssertQuery(
+            async,
+            ss => ss.Set<NodaTimeTypes>().Where(t => t.LocalDateTime.TimeOfDay == new LocalTime(10, 31, 33, 666)),
+            entryCount: 1);
+
+        AssertSql(
+"""
+SELECT n."Id", n."DateInterval", n."Duration", n."Instant", n."InstantRange", n."Interval", n."LocalDate", n."LocalDate2", n."LocalDateRange", n."LocalDateTime", n."LocalTime", n."Long", n."OffsetTime", n."Period", n."TimeZoneId", n."ZonedDateTime"
+FROM "NodaTimeTypes" AS n
+WHERE n."LocalDateTime"::time = TIME '10:31:33.666'
+""");
+    }
+
     [ConditionalTheory]
     [MemberData(nameof(IsAsyncData))]
     public async Task LocalDateTime_DayOfWeek(bool async)
@@ -324,8 +341,8 @@ await AssertQuery(
 """
 SELECT n."Id", n."DateInterval", n."Duration", n."Instant", n."InstantRange", n."Interval", n."LocalDate", n."LocalDate2", n."LocalDateRange", n."LocalDateTime", n."LocalTime", n."Long", n."OffsetTime", n."Period", n."TimeZoneId", n."ZonedDateTime"
 FROM "NodaTimeTypes" AS n
-WHERE CASE
-    WHEN floor(date_part('dow', n."LocalDateTime"))::int = 0 THEN 7
+WHERE CASE floor(date_part('dow', n."LocalDateTime"))::int
+    WHEN 0 THEN 7
     ELSE floor(date_part('dow', n."LocalDateTime"))::int
 END = 5
 """);
@@ -1812,8 +1829,8 @@ await AssertQuery(
 """
 SELECT n."Id", n."DateInterval", n."Duration", n."Instant", n."InstantRange", n."Interval", n."LocalDate", n."LocalDate2", n."LocalDateRange", n."LocalDateTime", n."LocalTime", n."Long", n."OffsetTime", n."Period", n."TimeZoneId", n."ZonedDateTime"
 FROM "NodaTimeTypes" AS n
-WHERE CASE
-    WHEN floor(date_part('dow', n."ZonedDateTime" AT TIME ZONE 'UTC'))::int = 0 THEN 7
+WHERE CASE floor(date_part('dow', n."ZonedDateTime" AT TIME ZONE 'UTC'))::int
+    WHEN 0 THEN 7
     ELSE floor(date_part('dow', n."ZonedDateTime" AT TIME ZONE 'UTC'))::int
 END = 5
 """);