Add DATALENGTH function to SqlServer

src/EFCore.SqlServer/Extensions/SqlServerDbFunctionsExtensions.cs

@@ -966,5 +966,104 @@ public static TimeSpan TimeFromParts(
             int fractions,
             int precision)
             => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(TimeFromParts)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            [CanBeNull] string arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            bool? arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            double? arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            decimal? arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            DateTime? arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            TimeSpan? arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            DateTimeOffset? arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            [CanBeNull] byte[] arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
+
+        /// <summary>
+        ///     Returns the number of bytes used to represent any expression.
+        /// </summary>
+        /// <param name="_">The DbFunctions instance.</param>
+        /// <param name="arg">The value to be examined for data length.</param>
+        /// <returns>The number of bytes in the input value.</returns>
+        public static int? DataLength(
+            [CanBeNull] this DbFunctions _,
+            Guid? arg)
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
     }
 }

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

@@ -0,0 +1,102 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using JetBrains.Annotations;
+using Microsoft.EntityFrameworkCore.Query;
+using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
+using Microsoft.EntityFrameworkCore.Utilities;
+
+namespace Microsoft.EntityFrameworkCore.SqlServer.Query.Internal
+{
+    public class SqlServerDataLengthFunctionTranslator : IMethodCallTranslator
+    {
+        private static readonly List<string> _longReturningTypes = new List<string> { "nvarchar(max)", "varchar(max)", "varbinary(max)" };
+
+        private static readonly HashSet<MethodInfo> _methodInfoDataLengthMapping
+            = new HashSet<MethodInfo>
+            {
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(string) }),
+
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(bool?) }),
+
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(double?) }),
+
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(decimal?) }),
+
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(DateTime?) }),
+
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(TimeSpan?) }),
+
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(DateTimeOffset?) }),
+
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(byte[]) }),
+
+                typeof(SqlServerDbFunctionsExtensions).GetRuntimeMethod(
+                    nameof(SqlServerDbFunctionsExtensions.DataLength),
+                    new[] { typeof(DbFunctions), typeof(Guid?) })
+            };
+
+        private readonly ISqlExpressionFactory _sqlExpressionFactory;
+
+        public SqlServerDataLengthFunctionTranslator([NotNull] ISqlExpressionFactory sqlExpressionFactory)
+        {
+            _sqlExpressionFactory = sqlExpressionFactory;
+        }
+
+        public virtual SqlExpression Translate(SqlExpression instance, MethodInfo method, IReadOnlyList<SqlExpression> arguments)
+        {
+            Check.NotNull(method, nameof(method));
+            Check.NotNull(arguments, nameof(arguments));
+
+            if (_methodInfoDataLengthMapping.Contains(method))
+            {
+                var argument = arguments[1];
+                if (argument.TypeMapping == null)
+                {
+                    argument = _sqlExpressionFactory.ApplyDefaultTypeMapping(argument);
+                }
+
+                if (_longReturningTypes.Contains(argument.TypeMapping.StoreType))
+                {
+                    var result = _sqlExpressionFactory.Function(
+                        "DATALENGTH",
+                        arguments.Skip(1),
+                        nullable: true,
+                        argumentsPropagateNullability: new[] { true },
+                        typeof(long));
+
+                    return _sqlExpressionFactory.Convert(result, method.ReturnType);
+                }
+
+                return _sqlExpressionFactory.Function(
+                    "DATALENGTH",
+                    arguments.Skip(1),
+                    nullable: true,
+                    argumentsPropagateNullability: new[] { true },
+                    method.ReturnType);
+            }
+
+            return null;
+        }
+    }
+}

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

@@ -18,6 +18,7 @@ public SqlServerMethodCallTranslatorProvider([NotNull] RelationalMethodCallTrans
                 {
                     new SqlServerByteArrayMethodTranslator(sqlExpressionFactory),
                     new SqlServerConvertTranslator(sqlExpressionFactory),
+                    new SqlServerDataLengthFunctionTranslator(sqlExpressionFactory),
                     new SqlServerDateDiffFunctionsTranslator(sqlExpressionFactory),
                     new SqlServerDateTimeMethodTranslator(sqlExpressionFactory),
                     new SqlServerFromPartsFunctionTranslator(sqlExpressionFactory, typeMappingSource),
@@ -26,7 +27,7 @@ public SqlServerMethodCallTranslatorProvider([NotNull] RelationalMethodCallTrans
                     new SqlServerMathTranslator(sqlExpressionFactory),
                     new SqlServerNewGuidTranslator(sqlExpressionFactory),
                     new SqlServerObjectToStringTranslator(sqlExpressionFactory),
-                    new SqlServerStringMethodTranslator(sqlExpressionFactory),
+                    new SqlServerStringMethodTranslator(sqlExpressionFactory)
                 });
         }
     }

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

@@ -2,7 +2,10 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Linq;
 using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore.TestModels.GearsOfWarModel;
+using Xunit;
 using Xunit.Abstractions;
 
 namespace Microsoft.EntityFrameworkCore.Query
@@ -6976,6 +6979,20 @@ FROM [Gears] AS [g]
 ORDER BY [g].[Nickname]");
         }
 
+        [ConditionalTheory]
+        [MemberData(nameof(IsAsyncData))]
+        public async Task DataLength_function_for_string_parameter(bool async)
+        {
+            await AssertQueryScalar(
+                async,
+                ss => ss.Set<Mission>().Select(m => EF.Functions.DataLength(m.CodeName)),
+                ss => ss.Set<Mission>().Select(m => (int?)(m.CodeName.Length * 2)));
+
+            AssertSql(
+                @"SELECT CAST(DATALENGTH([m].[CodeName]) AS int)
+FROM [Missions] AS [m]");
+        }
+
         private void AssertSql(params string[] expected)
             => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);
     }

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

@@ -967,6 +967,60 @@ FROM [Orders] AS [o]
             }