Fix OPENJSON AS JSON failure on Azure SQL when column type is json at compat level 170

src/EFCore.SqlServer/Query/Internal/SqlServerQuerySqlGenerator.cs

@@ -792,8 +792,22 @@ void GenerateColumnInfo(SqlServerOpenJsonExpression.ColumnInfo columnInfo)
             {
                 Sql
                     .Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(columnInfo.Name))
-                    .Append(" ")
-                    .Append(columnInfo.TypeMapping.StoreType);
+                    .Append(" ");
+
+                // OPENJSON() WITH clause AS JSON option requires nvarchar(max) on platforms that don't support the json data
+                // type in OPENJSON (i.e. Azure SQL). SQL Server 2025 (17.x) added native support for json in OPENJSON WITH.
+                // See: https://learn.microsoft.com/sql/t-sql/data-types/json-data-type#limitations
+                if (columnInfo.AsJson
+                    && columnInfo.TypeMapping.StoreType == "json"
+                    && (_sqlServerSingletonOptions.EngineType != SqlServerEngineType.SqlServer
+                        || _sqlServerSingletonOptions.SqlServerCompatibilityLevel < 170))
+                {
+                    Sql.Append("nvarchar(max)");
+                }
+                else
+                {
+                    Sql.Append(columnInfo.TypeMapping.StoreType);
+                }
 
                 if (columnInfo.Path is not null)
                 {

test/EFCore.Relational.Specification.Tests/Query/AdHocJsonQueryRelationalTestBase.cs

@@ -691,6 +691,99 @@ public class JsonNestedType
 
     #endregion HasJsonPropertyName
 
+    #region 38615
+
+    [ConditionalFact]
+    public virtual async Task SelectMany_over_primitive_collection_nested_in_complex_collection_inside_json_column()
+    {
+        var contextFactory = await InitializeAsync<Context38615>(
+            onConfiguring: b => b.ConfigureWarnings(ConfigureWarnings),
+            onModelCreating: m => m.Entity<Context38615.Car>(b =>
+            {
+                b.ToTable("Cars");
+                b.HasKey(e => e.CarId);
+                b.Property(e => e.Vin).IsUnicode(false).HasMaxLength(32);
+                b.Property(e => e.DealerId).IsUnicode(false).HasMaxLength(32);
+                b.HasIndex(e => new { e.Vin, e.DealerId }).IsUnique();
+
+                b.ComplexProperty(e => e.CarConfiguration, pp =>
+                {
+                    pp.ToJson("CarConfiguration");
+                    if (JsonColumnType != null)
+                    {
+                        pp.HasColumnType(JsonColumnType);
+                    }
+
+                    pp.Property(p => p.CurrentTrim).HasJsonPropertyName("currentTrim");
+
+                    pp.ComplexCollection(p => p.OptionPackages, op =>
+                    {
+                        op.HasJsonPropertyName("optionPackages");
+                        op.Property(o => o.PackageId).HasJsonPropertyName("packageId");
+                        op.PrimitiveCollection(o => o.PartNumbers)
+                            .ElementType(e => e.IsUnicode(false).HasMaxLength(32))
+                            .HasJsonPropertyName("partNumbers");
+                    });
+                });
+            }),
+            seed: context =>
+            {
+                context.Set<Context38615.Car>().Add(
+                    new Context38615.Car
+                    {
+                        Vin = "1FA6P8TH8J5123456",
+                        DealerId = "DEALER-001",
+                        CarConfiguration = new Context38615.CarConfiguration
+                        {
+                            CurrentTrim = "GT-Line",
+                            OptionPackages =
+                            [
+                                new Context38615.OptionPackage { PackageId = "PKG-SPORT", PartNumbers = ["SP-100", "SP-101"] },
+                                new Context38615.OptionPackage { PackageId = "PKG-TOW", PartNumbers = ["TW-200"] }
+                            ]
+                        }
+                    });
+
+                return context.SaveChangesAsync();
+            });
+
+        await using var context = contextFactory.CreateContext();
+
+        var partNumbers = await context.Set<Context38615.Car>()
+            .Where(c => c.Vin == "1FA6P8TH8J5123456" && c.DealerId == "DEALER-001")
+            .SelectMany(c => c.CarConfiguration.OptionPackages)
+            .Where(op => op.PackageId == "PKG-SPORT")
+            .SelectMany(op => op.PartNumbers)
+            .ToListAsync();
+
+        Assert.Equal(["SP-100", "SP-101"], partNumbers.Order().ToList());
+    }
+
+    protected class Context38615(DbContextOptions options) : DbContext(options)
+    {
+        public class Car
+        {
+            public int CarId { get; set; }
+            public string Vin { get; set; }
+            public string DealerId { get; set; }
+            public CarConfiguration CarConfiguration { get; set; }
+        }
+
+        public class CarConfiguration
+        {
+            public string CurrentTrim { get; set; }
+            public List<OptionPackage> OptionPackages { get; set; }
+        }
+
+        public class OptionPackage
+        {
+            public string PackageId { get; set; }
+            public ICollection<string> PartNumbers { get; set; }
+        }
+    }
+
+    #endregion 38615
+
     protected TestSqlLoggerFactory TestSqlLoggerFactory
         => (TestSqlLoggerFactory)ListLoggerFactory;
 

test/EFCore.SqlServer.FunctionalTests/Query/AdHocJsonQuerySqlServerTestBase.cs

@@ -680,4 +680,60 @@ FROM [MyEntity] AS [m]
 INNER JOIN [OtherTable] AS [o] ON [m].[Id] = [o].[Id]
 """);
     }
+
+    public override async Task SelectMany_over_primitive_collection_nested_in_complex_collection_inside_json_column()
+    {
+        await base.SelectMany_over_primitive_collection_nested_in_complex_collection_inside_json_column();
+
+        switch (JsonColumnType)
+        {
+            case "json":
+                if (Microsoft.EntityFrameworkCore.TestUtilities.TestEnvironment.IsAzureSql)
+                {
+                    AssertSql(
+                        """
+SELECT [p].[value]
+FROM [Cars] AS [c]
+CROSS APPLY OPENJSON([c].[CarConfiguration], '$.optionPackages') WITH (
+    [packageId] nvarchar(max) '$.packageId',
+    [partNumbers] nvarchar(max) '$.partNumbers' AS JSON
+) AS [o]
+CROSS APPLY OPENJSON([o].[partNumbers]) WITH ([value] varchar(32) '$') AS [p]
+WHERE [c].[Vin] = '1FA6P8TH8J5123456' AND [c].[DealerId] = 'DEALER-001' AND [o].[packageId] = N'PKG-SPORT'
+""");
+                }
+                else
+                {
+                    AssertSql(
+                        """
+SELECT [p].[value]
+FROM [Cars] AS [c]
+CROSS APPLY OPENJSON([c].[CarConfiguration], '$.optionPackages') WITH (
+    [packageId] nvarchar(max) '$.packageId',
+    [partNumbers] json '$.partNumbers' AS JSON
+) AS [o]
+CROSS APPLY OPENJSON([o].[partNumbers]) WITH ([value] varchar(32) '$') AS [p]
+WHERE [c].[Vin] = '1FA6P8TH8J5123456' AND [c].[DealerId] = 'DEALER-001' AND [o].[packageId] = N'PKG-SPORT'
+""");
+                }
+
+                break;
+            case "nvarchar(max)":
+                AssertSql(
+                    """
+SELECT [p].[value]
+FROM [Cars] AS [c]
+CROSS APPLY OPENJSON([c].[CarConfiguration], '$.optionPackages') WITH (
+    [packageId] nvarchar(max) '$.packageId',
+    [partNumbers] nvarchar(max) '$.partNumbers' AS JSON
+) AS [o]
+CROSS APPLY OPENJSON([o].[partNumbers]) WITH ([value] varchar(32) '$') AS [p]
+WHERE [c].[Vin] = '1FA6P8TH8J5123456' AND [c].[DealerId] = 'DEALER-001' AND [o].[packageId] = N'PKG-SPORT'
+""");
+                break;
+
+            default:
+                throw new UnreachableException();
+        }
+    }
 }

test/EFCore.Sqlite.FunctionalTests/Query/AdHocJsonQuerySqliteTest.cs

@@ -319,4 +319,8 @@ INSERT INTO Entities (Id, Scenario, OptionalReference, RequiredReference, Collec
 ]')
 """);
     }
+
+    public override Task SelectMany_over_primitive_collection_nested_in_complex_collection_inside_json_column()
+        => Assert.ThrowsAsync<InvalidOperationException>(
+            base.SelectMany_over_primitive_collection_nested_in_complex_collection_inside_json_column);
 }