Add JsonExists DbFunction

- Define SqlServer translation
- Define Sqllite translation

Fixes #31136

src/EFCore.Relational/Extensions/RelationalDbFunctionsExtensions.cs

@@ -56,4 +56,32 @@ public static T Greatest<T>(
         this DbFunctions _,
         [NotParameterized] params T[] values)
         => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(Greatest)));
+
+    /// <summary>
+    ///     Checks whether a specified JSON path exists within a JSON string.
+    ///     Typically corresponds to a database function or SQL expression.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         This method is translated to a database-specific function or expression. 
+    ///         The support for this function depends on the database and provider being used. 
+    ///         Refer to your database provider's documentation for detailed support information.
+    ///     </para>
+    ///     <para>
+    ///         For more details, see <see href="https://learn.microsoft.com/en-us/ef/core/providers">EF Core database providers</see>.
+    ///     </para>
+    /// </remarks>
+    /// <param name="_">The <see cref="DbFunctions"/> instance.</param>
+    /// <param name="expression">The JSON string or column containing JSON text.</param>
+    /// <param name="path">The JSON path to check for existence.</param>
+    /// <typeparam name="T">The type of the JSON expression.</typeparam>
+    /// <returns>
+    ///     A nullable boolean value, <see langword="true"/> if the JSON path exists, <see langword="false"/> if not, and <see langword="null"/>
+    ///     when the JSON string is null.
+    /// </returns>
+    public static bool? JsonExists<T>(
+        this DbFunctions _,
+        T expression,
+        string path)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(JsonExists)));
 }

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

@@ -38,6 +38,7 @@ public SqlServerMethodCallTranslatorProvider(
             new SqlServerFullTextSearchFunctionsTranslator(sqlExpressionFactory),
             new SqlServerIsDateFunctionTranslator(sqlExpressionFactory),
             new SqlServerIsNumericFunctionTranslator(sqlExpressionFactory),
+            new SqlServerJsonFunctionsTranslator(sqlExpressionFactory, sqlServerSingletonOptions),
             new SqlServerMathTranslator(sqlExpressionFactory),
             new SqlServerNewGuidTranslator(sqlExpressionFactory),
             new SqlServerObjectToStringTranslator(sqlExpressionFactory, typeMappingSource),

src/EFCore.SqlServer/Query/Internal/Translators/SqlServerJsonFunctionsTranslator.cs

@@ -0,0 +1,64 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
+using Microsoft.EntityFrameworkCore.SqlServer.Infrastructure.Internal;
+using Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal;
+
+// ReSharper disable once CheckNamespace
+namespace Microsoft.EntityFrameworkCore.SqlServer.Query.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 SqlServerJsonFunctionsTranslator : IMethodCallTranslator
+{
+    private static readonly MethodInfo JsonExistsMethodInfo = typeof(RelationalDbFunctionsExtensions)
+        .GetRuntimeMethod(nameof(RelationalDbFunctionsExtensions.JsonExists), [typeof(DbFunctions), typeof(object), typeof(string)])!;
+
+    private readonly ISqlExpressionFactory _sqlExpressionFactory;
+    private readonly ISqlServerSingletonOptions _sqlServerSingletonOptions;
+
+    /// <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 SqlServerJsonFunctionsTranslator(ISqlExpressionFactory sqlExpressionFactory, ISqlServerSingletonOptions sqlServerSingletonOptions)
+    {
+        _sqlExpressionFactory = sqlExpressionFactory;
+        _sqlServerSingletonOptions = sqlServerSingletonOptions;
+    }
+
+    /// <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(
+        SqlExpression? instance,
+        MethodInfo method,
+        IReadOnlyList<SqlExpression> arguments,
+        IDiagnosticsLogger<DbLoggerCategory.Query> logger)
+    {
+        if (JsonExistsMethodInfo.Equals(method)
+            && arguments[0].TypeMapping is SqlServerOwnedJsonTypeMapping or StringTypeMapping
+            && _sqlServerSingletonOptions.EngineType == SqlServerEngineType.SqlServer
+            && _sqlServerSingletonOptions.SqlServerCompatibilityLevel >= 160)
+        {
+            return _sqlExpressionFactory.Function(
+                "JSON_PATH_EXISTS",
+                arguments,
+                nullable: true,
+                argumentsPropagateNullability: Statics.TrueArrays[2],
+                method.ReturnType);
+        }
+
+        return null;
+    }
+}

src/EFCore.Sqlite.Core/Query/Internal/SqliteMethodCallTranslatorProvider.cs

@@ -30,6 +30,7 @@ public SqliteMethodCallTranslatorProvider(RelationalMethodCallTranslatorProvider
             new SqliteDateTimeMethodTranslator(sqlExpressionFactory),
             new SqliteGlobMethodTranslator(sqlExpressionFactory),
             new SqliteHexMethodTranslator(sqlExpressionFactory),
+            new SqliteJsonFunctionsTranslator(sqlExpressionFactory),
             new SqliteMathTranslator(sqlExpressionFactory),
             new SqliteObjectToStringTranslator(sqlExpressionFactory),
             new SqliteRandomTranslator(sqlExpressionFactory),

src/EFCore.Sqlite.Core/Query/Internal/Translators/SqliteJsonFunctionsTranslator.cs

@@ -0,0 +1,68 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
+using Microsoft.EntityFrameworkCore.Sqlite.Storage.Internal;
+
+// ReSharper disable once CheckNamespace
+namespace Microsoft.EntityFrameworkCore.Sqlite.Query.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 SqliteJsonFunctionsTranslator : IMethodCallTranslator
+{
+    private static readonly MethodInfo JsonExistsMethodInfo = typeof(RelationalDbFunctionsExtensions)
+        .GetRuntimeMethod(nameof(RelationalDbFunctionsExtensions.JsonExists), [typeof(DbFunctions), typeof(object), typeof(string)])!;
+
+    private readonly ISqlExpressionFactory _sqlExpressionFactory;
+
+    /// <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 SqliteJsonFunctionsTranslator(ISqlExpressionFactory sqlExpressionFactory)
+    {
+        _sqlExpressionFactory = sqlExpressionFactory;
+    }
+
+    /// <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(
+        SqlExpression? instance,
+        MethodInfo method,
+        IReadOnlyList<SqlExpression> arguments,
+        IDiagnosticsLogger<DbLoggerCategory.Query> logger)
+    {
+        if (JsonExistsMethodInfo.Equals(method)
+            && arguments[0].TypeMapping is SqliteJsonTypeMapping or StringTypeMapping)
+        {
+            // IIF(arguments_0 IS NULL, NULL, JSON_TYPE(arguments_0, arguments_1) IS NOT NULL)
+            return _sqlExpressionFactory.Function("IFF",
+                [
+                    _sqlExpressionFactory.IsNull(arguments[0]),
+                    _sqlExpressionFactory.Fragment("NULL", method.ReturnType),
+                    _sqlExpressionFactory.IsNotNull(
+                        _sqlExpressionFactory.Function("JSON_TYPE",
+                            arguments,
+                            nullable: true,
+                            argumentsPropagateNullability: Statics.TrueArrays[2],
+                            returnType: typeof(string)))
+                ],
+                nullable: true,
+                argumentsPropagateNullability: Statics.TrueArrays[3],
+                method.ReturnType);
+        }
+
+        return null;
+    }
+}