diff --git a/RepoDb.Core/RepoDb.Tests/RepoDb.IntegrationTests/EnumPropertyTest.cs b/RepoDb.Core/RepoDb.Tests/RepoDb.IntegrationTests/EnumPropertyTest.cs
index ebc96ad42..f99110f72 100644
--- a/RepoDb.Core/RepoDb.Tests/RepoDb.IntegrationTests/EnumPropertyTest.cs
+++ b/RepoDb.Core/RepoDb.Tests/RepoDb.IntegrationTests/EnumPropertyTest.cs
@@ -96,25 +96,25 @@ public void TestQueryGroupForEnumViaDynamic()
             }
         }
 
-        //[TestMethod]
-        //public void TestQueryGroupForEnumViaExpression()
-        //{
-        //    // Setup
-        //    var entities = Helper.CreateEnumCompleteTables(10);
-
-        //    using (var connection = new SqlConnection(Database.ConnectionStringForRepoDb))
-        //    {
-        //        // Act
-        //        var insertAllResult = connection.InsertAll<EnumCompleteTable>(entities);
-        //        var queryResult = connection.Query<EnumCompleteTable>(e => e.ColumnNVarChar == Direction.West);
-
-        //        // Assert
-        //        Assert.AreEqual(entities.Count, queryResult.Count());
-
-        //        // Assert
-        //        entities.ForEach(entity => Helper.AssertPropertiesEquality(entity, queryResult.Where(item => item.SessionId == entity.SessionId)));
-        //    }
-        //}
+        [TestMethod]
+        public void TestQueryGroupForEnumViaExpression()
+        {
+            // Setup
+            var entities = Helper.CreateEnumCompleteTables(10);
+
+            using (var connection = new SqlConnection(Database.ConnectionStringForRepoDb))
+            {
+                // Act
+                var insertAllResult = connection.InsertAll<EnumCompleteTable>(entities);
+                var queryResult = connection.Query<EnumCompleteTable>(e => e.ColumnNVarChar == Direction.West);
+
+                // Assert
+                Assert.AreEqual(entities.Count, queryResult.Count());
+
+                // Assert
+                entities.ForEach(entity => Helper.AssertPropertiesEquality(entity, queryResult.Where(item => item.SessionId == entity.SessionId)));
+            }
+        }
 
         [TestMethod]
         public void TestQueryGroupForEnumViaQueryField()
diff --git a/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseDynamicValuesTest.cs b/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseDynamicValuesTest.cs
index f373fb4de..5edd6a631 100644
--- a/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseDynamicValuesTest.cs
+++ b/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseDynamicValuesTest.cs
@@ -45,5 +45,20 @@ public void TestQueryGroupParseDynamicValueForMultipleFields()
             Assert.AreEqual(1, actual1);
             Assert.AreEqual(2, actual2);
         }
+
+        [TestMethod]
+        public void TestQueryGroupParseDynamicValueForEnums()
+        {
+            // Setup
+            var parsed = QueryGroup.Parse(new { Field1 = Direction.West, Field2 = Direction.East });
+
+            // Act
+            var actual1 = parsed.QueryFields.First().Parameter.Value;
+            var actual2 = parsed.QueryFields.Last().Parameter.Value;
+
+            // Assert
+            Assert.AreEqual(Direction.West, actual1);
+            Assert.AreEqual(Direction.East, actual2);
+        }
     }
 }
diff --git a/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionClassesTest.cs b/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionClassesTest.cs
index 10ceb82e3..59e1ceacf 100644
--- a/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionClassesTest.cs
+++ b/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionClassesTest.cs
@@ -11,6 +11,14 @@ public class QueryGroupTestExpressionClassMember
             public string PropertyString { get; set; }
         }
 
+        public enum Direction
+        {
+            North,
+            South,
+            East,
+            West
+        }
+
         public class QueryGroupTestExpressionClass
         {
             public int PropertyInt { get; set; }
@@ -21,6 +29,7 @@ public class QueryGroupTestExpressionClass
             public Guid PropertyGuid { get; set; }
             public Boolean PropertyBoolean { get; set; }
             public Byte[] PropertyBytes { get; set; }
+            public Direction Direction { get; set; }
             [Map("PropertyString")]
             public string OtherPropertyString { get; set; }
             public QueryGroupTestExpressionClassMember Member { get; set; }
diff --git a/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionForContainsMethodTest.cs b/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionForContainsMethodTest.cs
index f0383b91c..4dd3d88e0 100644
--- a/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionForContainsMethodTest.cs
+++ b/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionForContainsMethodTest.cs
@@ -514,7 +514,7 @@ public void TestQueryGroupParseExpressionArrayContainsEqualsFalse()
 
             // Act
             var actual = parsed.GetString();
-            var expected = "NOT ([PropertyInt] IN (@PropertyInt_In_0, @PropertyInt_In_1))";
+            var expected = "([PropertyInt] NOT IN (@PropertyInt_In_0, @PropertyInt_In_1))";
 
             // Assert
             Assert.AreEqual(expected, actual);
@@ -544,7 +544,7 @@ public void TestQueryGroupParseExpressionArrayContainsFromVariableEqualsFalse()
 
             // Act
             var actual = parsed.GetString();
-            var expected = "NOT ([PropertyInt] IN (@PropertyInt_In_0, @PropertyInt_In_1))";
+            var expected = "([PropertyInt] NOT IN (@PropertyInt_In_0, @PropertyInt_In_1))";
 
             // Assert
             Assert.AreEqual(expected, actual);
@@ -662,7 +662,7 @@ public void TestQueryGroupParseExpressionListContainsEqualsFalse()
 
             // Act
             var actual = parsed.GetString();
-            var expected = "NOT ([PropertyInt] IN (@PropertyInt_In_0, @PropertyInt_In_1))";
+            var expected = "([PropertyInt] NOT IN (@PropertyInt_In_0, @PropertyInt_In_1))";
 
             // Assert
             Assert.AreEqual(expected, actual);
@@ -692,7 +692,7 @@ public void TestQueryGroupParseExpressionListContainsFromVariableEqualsFalse()
 
             // Act
             var actual = parsed.GetString();
-            var expected = "NOT ([PropertyInt] IN (@PropertyInt_In_0, @PropertyInt_In_1))";
+            var expected = "([PropertyInt] NOT IN (@PropertyInt_In_0, @PropertyInt_In_1))";
 
             // Assert
             Assert.AreEqual(expected, actual);
diff --git a/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionValuesTest.cs b/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionValuesTest.cs
index de1ec793c..329d1a73f 100644
--- a/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionValuesTest.cs
+++ b/RepoDb.Core/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionValuesTest.cs
@@ -6,7 +6,7 @@ namespace RepoDb.UnitTests
 {
     public partial class QueryGroupTest
     {
-        // Values
+        #region Values
 
         [TestMethod]
         public void TestQueryGroupParseExpressionValueIntConstant()
@@ -362,7 +362,9 @@ public void TestQueryGroupParseExpressionWithDefaultValue()
             Assert.AreEqual(expected, actual);
         }
 
-        // Contains
+        #endregion
+
+        #region Contains
 
         [TestMethod]
         public void TestQueryGroupParseExpressionValueForStringPropertyContains()
@@ -522,7 +524,9 @@ public void TestQueryGroupParseExpressionValueForArrayNotContainsEqualsFalse()
             Assert.AreEqual("B", ((Array)actual).GetValue(1));
         }
 
-        // All
+        #endregion
+
+        #region All
 
         [TestMethod]
         public void TestQueryGroupParseExpressionValueForArrayAll()
@@ -613,7 +617,9 @@ public void TestQueryGroupParseExpressionValueForArrayNotAllEqualsTrue()
             Assert.AreEqual("B", actual2);
         }
 
-        // Any
+        #endregion
+
+        #region Any
 
         [TestMethod]
         public void TestQueryGroupParseExpressionValueForArrayAny()
@@ -703,5 +709,39 @@ public void TestQueryGroupParseExpressionValueForArrayNotAnyEqualsTrue()
             Assert.AreEqual("A", actual1);
             Assert.AreEqual("B", actual2);
         }
+
+        #endregion
+
+        #region Enums
+
+        [TestMethod]
+        public void TestQueryGroupParseExpressionValueForEnum()
+        {
+            // Setup
+            var parsed = QueryGroup.Parse<QueryGroupTestExpressionClass>(p => p.Direction == Direction.East);
+
+            // Act
+            var actual = parsed.QueryFields.First().Parameter.Value;
+
+            // Assert
+            Assert.AreEqual(Direction.East, actual);
+        }
+
+        [TestMethod]
+        public void TestQueryGroupParseExpressionValueForEnums()
+        {
+            // Setup
+            var parsed = QueryGroup.Parse<QueryGroupTestExpressionClass>(p => p.Direction == Direction.East || p.Direction == Direction.West);
+
+            // Act
+            var actual1 = parsed.QueryGroups.First().QueryFields.First().Parameter.Value;
+            var actual2 = parsed.QueryGroups.Last().QueryFields.First().Parameter.Value;
+
+            // Assert
+            Assert.AreEqual(Direction.East, actual1);
+            Assert.AreEqual(Direction.West, actual2);
+        }
+
+        #endregion
     }
 }
diff --git a/RepoDb.Core/RepoDb/Extensions/ExpressionExtension.cs b/RepoDb.Core/RepoDb/Extensions/ExpressionExtension.cs
index a72746f35..27fc24d64 100644
--- a/RepoDb.Core/RepoDb/Extensions/ExpressionExtension.cs
+++ b/RepoDb.Core/RepoDb/Extensions/ExpressionExtension.cs
@@ -39,7 +39,7 @@ public static class ExpressionExtension
         /// </summary>
         /// <param name="expression">The instance of <see cref="Expression"/> object to be identified.</param>
         /// <returns>Returns true if the expression can be extracted as <see cref="QueryField"/> object.</returns>
-        public static bool IsExtractable(this Expression expression)
+        internal static bool IsExtractable(this Expression expression)
         {
             return m_extractableExpressionTypes.Contains(expression.NodeType);
         }
@@ -49,7 +49,7 @@ public static bool IsExtractable(this Expression expression)
         /// </summary>
         /// <param name="expression">The instance of <see cref="Expression"/> object to be identified.</param>
         /// <returns>Returns true if the expression can be grouped as <see cref="QueryGroup"/> object.</returns>
-        public static bool IsGroupable(this Expression expression)
+        internal static bool IsGroupable(this Expression expression)
         {
             return expression.NodeType == ExpressionType.AndAlso || expression.NodeType == ExpressionType.OrElse;
         }
@@ -59,7 +59,7 @@ public static bool IsGroupable(this Expression expression)
         /// </summary>
         /// <param name="expression">The instance of <see cref="Expression"/> object to be identified.</param>
         /// <returns>Returns true if the expression is using the <see cref="Math"/> object operations.</returns>
-        public static bool IsMathematical(this Expression expression)
+        internal static bool IsMathematical(this Expression expression)
         {
             return m_mathematicalExpressionTypes.Contains(expression.NodeType);
         }
diff --git a/RepoDb.Core/RepoDb/Extensions/StringExtension.cs b/RepoDb.Core/RepoDb/Extensions/StringExtension.cs
index 0ced4be83..be5cf3d35 100644
--- a/RepoDb.Core/RepoDb/Extensions/StringExtension.cs
+++ b/RepoDb.Core/RepoDb/Extensions/StringExtension.cs
@@ -37,12 +37,22 @@ internal static string AsAlphaNumeric(this string value, bool trim = false)
         }
 
         /// <summary>
-        /// Removes the database quotes from the string.
+        /// Unquotes a string.
         /// </summary>
-        /// <param name="value">The string value where the database quotes will be removed.</param>
+        /// <param name="value">The string value to be unqouted.</param>
+        /// <returns>The unquoted string.</returns>
+        public static string AsUnquoted(this string value)
+        {
+            return Regex.Replace(value, @"[\[\]']+", "");
+        }
+
+        /// <summary>
+        /// Unquotes a string.
+        /// </summary>
+        /// <param name="value">The string value to be unqouted.</param>
         /// <param name="trim">The boolean value that indicates whether to trim the string before unquoting.</param>
         /// <param name="separator">The separator in which the quotes will be removed.</param>
-        /// <returns>The quoted string.</returns>
+        /// <returns>The unquoted string.</returns>
         public static string AsUnquoted(this string value, bool trim = false, string separator = ".")
         {
             if (trim)
@@ -62,19 +72,27 @@ public static string AsUnquoted(this string value, bool trim = false, string sep
         }
 
         /// <summary>
-        /// Remove the quotes from the string.
+        /// Quotes a string.
         /// </summary>
-        /// <param name="value">The string value where the database quotes will be removed.</param>
-        /// <returns></returns>
-        private static string AsUnquoted(this string value)
+        /// <param name="value">The string value to be quoted.</param>
+        /// <returns>The quoted string.</returns>
+        public static string AsQuoted(this string value)
         {
-            return Regex.Replace(value, @"[\[\]']+", "");
+            if (!value.StartsWith("["))
+            {
+                value = string.Concat("[", value);
+            }
+            if (!value.EndsWith("]"))
+            {
+                value = string.Concat(value, "]");
+            }
+            return value;
         }
 
         /// <summary>
-        /// Adds a quotes to the string.
+        /// Quotes a string.
         /// </summary>
-        /// <param name="value">The string value where the database quotes will be added.</param>
+        /// <param name="value">The string value to be quoted.</param>
         /// <param name="trim">The boolean value that indicates whether to trim the string before quoting.</param>
         /// <param name="separator">The separator in which the quotes will be placed.</param>
         /// <returns>The quoted string.</returns>
@@ -95,24 +113,6 @@ public static string AsQuoted(this string value, bool trim = false, string separ
             }
         }
 
-        /// <summary>
-        /// Add the quotes into the string.
-        /// </summary>
-        /// <param name="value">The string value where the database quotes will be added.</param>
-        /// <returns></returns>
-        private static string AsQuoted(this string value)
-        {
-            if (!value.StartsWith("["))
-            {
-                value = string.Concat("[", value);
-            }
-            if (!value.EndsWith("]"))
-            {
-                value = string.Concat(value, "]");
-            }
-            return value;
-        }
-
         // AsEnumerable
         internal static IEnumerable<string> AsEnumerable(this string value)
         {
diff --git a/RepoDb.Core/RepoDb/QueryGroup.cs b/RepoDb.Core/RepoDb/QueryGroup.cs
index d590b82b2..89c4165b6 100644
--- a/RepoDb.Core/RepoDb/QueryGroup.cs
+++ b/RepoDb.Core/RepoDb/QueryGroup.cs
@@ -664,11 +664,11 @@ private static QueryGroup Parse<TEntity>(Expression expression) where TEntity :
             }
             else if (expression.IsUnary())
             {
-                return Parse<TEntity>(expression.ToUnary(), expression.NodeType);
+                return Parse<TEntity>(expression.ToUnary(), null, expression.NodeType, true);
             }
             else if (expression.IsMethodCall())
             {
-                return Parse<TEntity>(expression.ToMethodCall());
+                return Parse<TEntity>(expression.ToMethodCall(), false, true);
             }
             return null;
         }
@@ -677,6 +677,7 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
         {
             var leftQueryGroup = (QueryGroup)null;
             var rightQueryGroup = (QueryGroup)null;
+            var rightValue = (object)null;
             var skipRight = false;
             var isEqualsTo = true;
 
@@ -684,19 +685,15 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
              * LEFT
              */
 
-            // Get the value in the right for (IsNot)
-            if (expression.Type == typeof(bool) && (expression.Right.IsConstant() || expression.Right.IsMember()))
+            // Get the value in the right
+            if (expression.IsExtractable())
             {
-                var value = expression.Right.GetValue();
-                if (value is bool)
-                {
-                    isEqualsTo = Equals(value, false) == false;
-                }
-                else
+                rightValue = expression.Right.GetValue();
+                skipRight = true;
+                if (rightValue is bool)
                 {
-                    // TODO: Fix the issue of the Enum for the Expression-Based Query
+                    isEqualsTo = Equals(rightValue, false) == false;
                 }
-                skipRight = true;
             }
 
             // Binary
@@ -708,12 +705,12 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
             // Unary
             else if (expression.Left.IsUnary() == true)
             {
-                leftQueryGroup = Parse<TEntity>(expression.Left.ToUnary(), expression.NodeType, isEqualsTo: isEqualsTo);
+                leftQueryGroup = Parse<TEntity>(expression.Left.ToUnary(), rightValue, expression.NodeType, isEqualsTo);
             }
             // MethodCall
             else if (expression.Left.IsMethodCall())
             {
-                leftQueryGroup = Parse<TEntity>(expression.Left.ToMethodCall(), isEqualsTo: isEqualsTo);
+                leftQueryGroup = Parse<TEntity>(expression.Left.ToMethodCall(), false, isEqualsTo);
             }
             else
             {
@@ -743,14 +740,14 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
                     rightQueryGroup = Parse<TEntity>(expression.Right.ToBinary());
                 }
                 // Unary
-                if (expression.Right.IsUnary() == true)
+                else if (expression.Right.IsUnary() == true)
                 {
-                    rightQueryGroup = Parse<TEntity>(expression.Right.ToUnary(), expression.NodeType);
+                    rightQueryGroup = Parse<TEntity>(expression.Right.ToUnary(), null, expression.NodeType, true);
                 }
                 // MethodCall
                 else if (expression.Right.IsMethodCall())
                 {
-                    rightQueryGroup = Parse<TEntity>(expression.Right.ToMethodCall());
+                    rightQueryGroup = Parse<TEntity>(expression.Right.ToMethodCall(), false, true);
                 }
 
                 // Return both of them
@@ -765,11 +762,11 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
             return leftQueryGroup ?? rightQueryGroup;
         }
 
-        private static QueryGroup Parse<TEntity>(UnaryExpression expression, ExpressionType expressionType, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup Parse<TEntity>(UnaryExpression expression, object rightValue, ExpressionType expressionType, bool isEqualsTo) where TEntity : class
         {
             if (expression.Operand?.IsMember() == true)
             {
-                return Parse<TEntity>(expression.Operand.ToMember(), expressionType);
+                return Parse<TEntity>(expression.Operand.ToMember(), rightValue, expressionType, false, true);
             }
             else if (expression.Operand?.IsMethodCall() == true)
             {
@@ -778,38 +775,36 @@ private static QueryGroup Parse<TEntity>(UnaryExpression expression, ExpressionT
             return null;
         }
 
-        private static QueryGroup Parse<TEntity>(MemberExpression expression, ExpressionType expressionType, bool isNot = false, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup Parse<TEntity>(MemberExpression expression, object rightValue, ExpressionType expressionType, bool isNot, bool isEqualsTo) where TEntity : class
         {
             var queryGroup = (QueryGroup)null;
-            var value = expression.GetValue();
+            var value = rightValue ?? expression.GetValue();
+
+            // Check if there are values
             if (value != null)
             {
-                #region Enum
-
+                // Specialized for enum
                 if (expression.Type.GetTypeInfo().IsEnum)
                 {
                     var dbType = TypeMapper.Get(expression.Type);
-                    if (dbType != null && dbType.Value != DbType.String)
-                    {
-                        var mappedToType = new SqlDbTypeToClientTypeResolver().Resolve(dbType.Value);
-                        var convertMethod = typeof(Convert).GetMethod(string.Concat("To", mappedToType.Name), new[] { typeof(object) });
-                        if (convertMethod != null)
-                        {
-                            value = convertMethod.Invoke(null, new[] { value });
-                        }
-                    }
+                    value = Enum.ToObject(expression.Type, value);
                 }
 
-                #endregion
-
+                // Create a new field
                 var field = new QueryField(expression.Member.GetMappedName(), QueryField.GetOperation(expressionType), value);
-                queryGroup = new QueryGroup(field.AsEnumerable());
+
+                // Set the query group
+                queryGroup = new QueryGroup(field);
+
+                // Set the query group IsNot property
                 queryGroup.SetIsNot(isEqualsTo == false);
             }
+
+            // Return the result
             return queryGroup;
         }
 
-        private static QueryGroup Parse<TEntity>(MethodCallExpression expression, bool isNot = false, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup Parse<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo) where TEntity : class
         {
             // Check methods for the 'Like', both 'Array.<All|Any>()'
             if (expression.Method.Name == "All" || expression.Method.Name == "Any")
@@ -858,7 +853,7 @@ private static QueryGroup Parse<TEntity>(MethodCallExpression expression, bool i
             return null;
         }
 
-        private static QueryGroup ParseAllOrAnyForArrayOrAnyForList<TEntity>(MethodCallExpression expression, bool isNot = false, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup ParseAllOrAnyForArrayOrAnyForList<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo) where TEntity : class
         {
             // Return null if there is no any arguments
             if (expression.Arguments?.Any() != true)
@@ -947,7 +942,7 @@ private static QueryGroup ParseAllOrAnyForArrayOrAnyForList<TEntity>(MethodCallE
             return new QueryGroup(queryFields, null, conjunction, (isNot == isEqualsTo));
         }
 
-        private static QueryGroup ParseContainsForArrayOrList<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup ParseContainsForArrayOrList<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo) where TEntity : class
         {
             // Return null if there is no any arguments
             if (expression.Arguments?.Any() != true)
@@ -1004,20 +999,20 @@ private static QueryGroup ParseContainsForArrayOrList<TEntity>(MethodCallExpress
             }
 
             // Add to query fields
-            var operation = isNot ? Operation.NotIn : Operation.In;
+            var operation = (isNot == false && isEqualsTo == true) ? Operation.In : Operation.NotIn;
             var queryField = new QueryField(property.Name, operation, values);
 
             // Return the result
             var queryGroup = new QueryGroup(queryField);
 
             // Set the IsNot value
-            queryGroup.SetIsNot(isEqualsTo == false);
+            queryGroup.SetIsNot(isNot == true && isEqualsTo == false);
 
             // Return the instance
             return queryGroup;
         }
 
-        private static QueryGroup ParseContainsOrStartsWithOrEndsWithForStringProperty<TEntity>(MethodCallExpression expression, bool isNot = false, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup ParseContainsOrStartsWithOrEndsWithForStringProperty<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo) where TEntity : class
         {
             // Return null if there is no any arguments
             if (expression.Arguments?.Any() != true)
diff --git a/RepoDb/RepoDb.Tests/RepoDb.IntegrationTests/EnumPropertyTest.cs b/RepoDb/RepoDb.Tests/RepoDb.IntegrationTests/EnumPropertyTest.cs
index ebc96ad42..f99110f72 100644
--- a/RepoDb/RepoDb.Tests/RepoDb.IntegrationTests/EnumPropertyTest.cs
+++ b/RepoDb/RepoDb.Tests/RepoDb.IntegrationTests/EnumPropertyTest.cs
@@ -96,25 +96,25 @@ public void TestQueryGroupForEnumViaDynamic()
             }
         }
 
-        //[TestMethod]
-        //public void TestQueryGroupForEnumViaExpression()
-        //{
-        //    // Setup
-        //    var entities = Helper.CreateEnumCompleteTables(10);
-
-        //    using (var connection = new SqlConnection(Database.ConnectionStringForRepoDb))
-        //    {
-        //        // Act
-        //        var insertAllResult = connection.InsertAll<EnumCompleteTable>(entities);
-        //        var queryResult = connection.Query<EnumCompleteTable>(e => e.ColumnNVarChar == Direction.West);
-
-        //        // Assert
-        //        Assert.AreEqual(entities.Count, queryResult.Count());
-
-        //        // Assert
-        //        entities.ForEach(entity => Helper.AssertPropertiesEquality(entity, queryResult.Where(item => item.SessionId == entity.SessionId)));
-        //    }
-        //}
+        [TestMethod]
+        public void TestQueryGroupForEnumViaExpression()
+        {
+            // Setup
+            var entities = Helper.CreateEnumCompleteTables(10);
+
+            using (var connection = new SqlConnection(Database.ConnectionStringForRepoDb))
+            {
+                // Act
+                var insertAllResult = connection.InsertAll<EnumCompleteTable>(entities);
+                var queryResult = connection.Query<EnumCompleteTable>(e => e.ColumnNVarChar == Direction.West);
+
+                // Assert
+                Assert.AreEqual(entities.Count, queryResult.Count());
+
+                // Assert
+                entities.ForEach(entity => Helper.AssertPropertiesEquality(entity, queryResult.Where(item => item.SessionId == entity.SessionId)));
+            }
+        }
 
         [TestMethod]
         public void TestQueryGroupForEnumViaQueryField()
diff --git a/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseDynamicValuesTest.cs b/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseDynamicValuesTest.cs
index f373fb4de..5edd6a631 100644
--- a/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseDynamicValuesTest.cs
+++ b/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseDynamicValuesTest.cs
@@ -45,5 +45,20 @@ public void TestQueryGroupParseDynamicValueForMultipleFields()
             Assert.AreEqual(1, actual1);
             Assert.AreEqual(2, actual2);
         }
+
+        [TestMethod]
+        public void TestQueryGroupParseDynamicValueForEnums()
+        {
+            // Setup
+            var parsed = QueryGroup.Parse(new { Field1 = Direction.West, Field2 = Direction.East });
+
+            // Act
+            var actual1 = parsed.QueryFields.First().Parameter.Value;
+            var actual2 = parsed.QueryFields.Last().Parameter.Value;
+
+            // Assert
+            Assert.AreEqual(Direction.West, actual1);
+            Assert.AreEqual(Direction.East, actual2);
+        }
     }
 }
diff --git a/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionClassesTest.cs b/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionClassesTest.cs
index 10ceb82e3..59e1ceacf 100644
--- a/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionClassesTest.cs
+++ b/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionClassesTest.cs
@@ -11,6 +11,14 @@ public class QueryGroupTestExpressionClassMember
             public string PropertyString { get; set; }
         }
 
+        public enum Direction
+        {
+            North,
+            South,
+            East,
+            West
+        }
+
         public class QueryGroupTestExpressionClass
         {
             public int PropertyInt { get; set; }
@@ -21,6 +29,7 @@ public class QueryGroupTestExpressionClass
             public Guid PropertyGuid { get; set; }
             public Boolean PropertyBoolean { get; set; }
             public Byte[] PropertyBytes { get; set; }
+            public Direction Direction { get; set; }
             [Map("PropertyString")]
             public string OtherPropertyString { get; set; }
             public QueryGroupTestExpressionClassMember Member { get; set; }
diff --git a/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionForContainsMethodTest.cs b/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionForContainsMethodTest.cs
index f0383b91c..4dd3d88e0 100644
--- a/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionForContainsMethodTest.cs
+++ b/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionForContainsMethodTest.cs
@@ -514,7 +514,7 @@ public void TestQueryGroupParseExpressionArrayContainsEqualsFalse()
 
             // Act
             var actual = parsed.GetString();
-            var expected = "NOT ([PropertyInt] IN (@PropertyInt_In_0, @PropertyInt_In_1))";
+            var expected = "([PropertyInt] NOT IN (@PropertyInt_In_0, @PropertyInt_In_1))";
 
             // Assert
             Assert.AreEqual(expected, actual);
@@ -544,7 +544,7 @@ public void TestQueryGroupParseExpressionArrayContainsFromVariableEqualsFalse()
 
             // Act
             var actual = parsed.GetString();
-            var expected = "NOT ([PropertyInt] IN (@PropertyInt_In_0, @PropertyInt_In_1))";
+            var expected = "([PropertyInt] NOT IN (@PropertyInt_In_0, @PropertyInt_In_1))";
 
             // Assert
             Assert.AreEqual(expected, actual);
@@ -662,7 +662,7 @@ public void TestQueryGroupParseExpressionListContainsEqualsFalse()
 
             // Act
             var actual = parsed.GetString();
-            var expected = "NOT ([PropertyInt] IN (@PropertyInt_In_0, @PropertyInt_In_1))";
+            var expected = "([PropertyInt] NOT IN (@PropertyInt_In_0, @PropertyInt_In_1))";
 
             // Assert
             Assert.AreEqual(expected, actual);
@@ -692,7 +692,7 @@ public void TestQueryGroupParseExpressionListContainsFromVariableEqualsFalse()
 
             // Act
             var actual = parsed.GetString();
-            var expected = "NOT ([PropertyInt] IN (@PropertyInt_In_0, @PropertyInt_In_1))";
+            var expected = "([PropertyInt] NOT IN (@PropertyInt_In_0, @PropertyInt_In_1))";
 
             // Assert
             Assert.AreEqual(expected, actual);
diff --git a/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionValuesTest.cs b/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionValuesTest.cs
index de1ec793c..329d1a73f 100644
--- a/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionValuesTest.cs
+++ b/RepoDb/RepoDb.Tests/RepoDb.UnitTests/QueryGroups/QueryGroupParseExpressionValuesTest.cs
@@ -6,7 +6,7 @@ namespace RepoDb.UnitTests
 {
     public partial class QueryGroupTest
     {
-        // Values
+        #region Values
 
         [TestMethod]
         public void TestQueryGroupParseExpressionValueIntConstant()
@@ -362,7 +362,9 @@ public void TestQueryGroupParseExpressionWithDefaultValue()
             Assert.AreEqual(expected, actual);
         }
 
-        // Contains
+        #endregion
+
+        #region Contains
 
         [TestMethod]
         public void TestQueryGroupParseExpressionValueForStringPropertyContains()
@@ -522,7 +524,9 @@ public void TestQueryGroupParseExpressionValueForArrayNotContainsEqualsFalse()
             Assert.AreEqual("B", ((Array)actual).GetValue(1));
         }
 
-        // All
+        #endregion
+
+        #region All
 
         [TestMethod]
         public void TestQueryGroupParseExpressionValueForArrayAll()
@@ -613,7 +617,9 @@ public void TestQueryGroupParseExpressionValueForArrayNotAllEqualsTrue()
             Assert.AreEqual("B", actual2);
         }
 
-        // Any
+        #endregion
+
+        #region Any
 
         [TestMethod]
         public void TestQueryGroupParseExpressionValueForArrayAny()
@@ -703,5 +709,39 @@ public void TestQueryGroupParseExpressionValueForArrayNotAnyEqualsTrue()
             Assert.AreEqual("A", actual1);
             Assert.AreEqual("B", actual2);
         }
+
+        #endregion
+
+        #region Enums
+
+        [TestMethod]
+        public void TestQueryGroupParseExpressionValueForEnum()
+        {
+            // Setup
+            var parsed = QueryGroup.Parse<QueryGroupTestExpressionClass>(p => p.Direction == Direction.East);
+
+            // Act
+            var actual = parsed.QueryFields.First().Parameter.Value;
+
+            // Assert
+            Assert.AreEqual(Direction.East, actual);
+        }
+
+        [TestMethod]
+        public void TestQueryGroupParseExpressionValueForEnums()
+        {
+            // Setup
+            var parsed = QueryGroup.Parse<QueryGroupTestExpressionClass>(p => p.Direction == Direction.East || p.Direction == Direction.West);
+
+            // Act
+            var actual1 = parsed.QueryGroups.First().QueryFields.First().Parameter.Value;
+            var actual2 = parsed.QueryGroups.Last().QueryFields.First().Parameter.Value;
+
+            // Assert
+            Assert.AreEqual(Direction.East, actual1);
+            Assert.AreEqual(Direction.West, actual2);
+        }
+
+        #endregion
     }
 }
diff --git a/RepoDb/RepoDb/Extensions/ExpressionExtension.cs b/RepoDb/RepoDb/Extensions/ExpressionExtension.cs
index d8327bdf2..ffbf7eba2 100644
--- a/RepoDb/RepoDb/Extensions/ExpressionExtension.cs
+++ b/RepoDb/RepoDb/Extensions/ExpressionExtension.cs
@@ -39,7 +39,7 @@ public static class ExpressionExtension
         /// </summary>
         /// <param name="expression">The instance of <see cref="Expression"/> object to be identified.</param>
         /// <returns>Returns true if the expression can be extracted as <see cref="QueryField"/> object.</returns>
-        public static bool IsExtractable(this Expression expression)
+        internal static bool IsExtractable(this Expression expression)
         {
             return m_extractableExpressionTypes.Contains(expression.NodeType);
         }
@@ -49,7 +49,7 @@ public static bool IsExtractable(this Expression expression)
         /// </summary>
         /// <param name="expression">The instance of <see cref="Expression"/> object to be identified.</param>
         /// <returns>Returns true if the expression can be grouped as <see cref="QueryGroup"/> object.</returns>
-        public static bool IsGroupable(this Expression expression)
+        internal static bool IsGroupable(this Expression expression)
         {
             return expression.NodeType == ExpressionType.AndAlso || expression.NodeType == ExpressionType.OrElse;
         }
@@ -59,7 +59,7 @@ public static bool IsGroupable(this Expression expression)
         /// </summary>
         /// <param name="expression">The instance of <see cref="Expression"/> object to be identified.</param>
         /// <returns>Returns true if the expression is using the <see cref="Math"/> object operations.</returns>
-        public static bool IsMathematical(this Expression expression)
+        internal static bool IsMathematical(this Expression expression)
         {
             return m_mathematicalExpressionTypes.Contains(expression.NodeType);
         }
diff --git a/RepoDb/RepoDb/QueryGroup.cs b/RepoDb/RepoDb/QueryGroup.cs
index 3bcfa9eba..826a5dc9e 100644
--- a/RepoDb/RepoDb/QueryGroup.cs
+++ b/RepoDb/RepoDb/QueryGroup.cs
@@ -664,11 +664,11 @@ private static QueryGroup Parse<TEntity>(Expression expression) where TEntity :
             }
             else if (expression.IsUnary())
             {
-                return Parse<TEntity>(expression.ToUnary(), expression.NodeType);
+                return Parse<TEntity>(expression.ToUnary(), null, expression.NodeType, true);
             }
             else if (expression.IsMethodCall())
             {
-                return Parse<TEntity>(expression.ToMethodCall());
+                return Parse<TEntity>(expression.ToMethodCall(), false, true);
             }
             return null;
         }
@@ -677,6 +677,7 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
         {
             var leftQueryGroup = (QueryGroup)null;
             var rightQueryGroup = (QueryGroup)null;
+            var rightValue = (object)null;
             var skipRight = false;
             var isEqualsTo = true;
 
@@ -684,19 +685,15 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
              * LEFT
              */
 
-            // Get the value in the right for (IsNot)
-            if (expression.Type == typeof(bool) && (expression.Right.IsConstant() || expression.Right.IsMember()))
+            // Get the value in the right
+            if (expression.IsExtractable())
             {
-                var value = expression.Right.GetValue();
-                if (value is bool)
-                {
-                    isEqualsTo = Equals(value, false) == false;
-                }
-                else
+                rightValue = expression.Right.GetValue();
+                skipRight = true;
+                if (rightValue is bool)
                 {
-                    // TODO: Fix the issue of the Enum for the Expression-Based Query
+                    isEqualsTo = Equals(rightValue, false) == false;
                 }
-                skipRight = true;
             }
 
             // Binary
@@ -708,12 +705,12 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
             // Unary
             else if (expression.Left.IsUnary() == true)
             {
-                leftQueryGroup = Parse<TEntity>(expression.Left.ToUnary(), expression.NodeType, isEqualsTo: isEqualsTo);
+                leftQueryGroup = Parse<TEntity>(expression.Left.ToUnary(), rightValue, expression.NodeType, isEqualsTo);
             }
             // MethodCall
             else if (expression.Left.IsMethodCall())
             {
-                leftQueryGroup = Parse<TEntity>(expression.Left.ToMethodCall(), isEqualsTo: isEqualsTo);
+                leftQueryGroup = Parse<TEntity>(expression.Left.ToMethodCall(), false, isEqualsTo);
             }
             else
             {
@@ -743,14 +740,14 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
                     rightQueryGroup = Parse<TEntity>(expression.Right.ToBinary());
                 }
                 // Unary
-                if (expression.Right.IsUnary() == true)
+                else if (expression.Right.IsUnary() == true)
                 {
-                    rightQueryGroup = Parse<TEntity>(expression.Right.ToUnary(), expression.NodeType);
+                    rightQueryGroup = Parse<TEntity>(expression.Right.ToUnary(), null, expression.NodeType, true);
                 }
                 // MethodCall
                 else if (expression.Right.IsMethodCall())
                 {
-                    rightQueryGroup = Parse<TEntity>(expression.Right.ToMethodCall());
+                    rightQueryGroup = Parse<TEntity>(expression.Right.ToMethodCall(), false, true);
                 }
 
                 // Return both of them
@@ -765,11 +762,11 @@ private static QueryGroup Parse<TEntity>(BinaryExpression expression) where TEnt
             return leftQueryGroup ?? rightQueryGroup;
         }
 
-        private static QueryGroup Parse<TEntity>(UnaryExpression expression, ExpressionType expressionType, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup Parse<TEntity>(UnaryExpression expression, object rightValue, ExpressionType expressionType, bool isEqualsTo) where TEntity : class
         {
             if (expression.Operand?.IsMember() == true)
             {
-                return Parse<TEntity>(expression.Operand.ToMember(), expressionType);
+                return Parse<TEntity>(expression.Operand.ToMember(), rightValue, expressionType, false, true);
             }
             else if (expression.Operand?.IsMethodCall() == true)
             {
@@ -778,38 +775,36 @@ private static QueryGroup Parse<TEntity>(UnaryExpression expression, ExpressionT
             return null;
         }
 
-        private static QueryGroup Parse<TEntity>(MemberExpression expression, ExpressionType expressionType, bool isNot = false, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup Parse<TEntity>(MemberExpression expression, object rightValue, ExpressionType expressionType, bool isNot, bool isEqualsTo) where TEntity : class
         {
             var queryGroup = (QueryGroup)null;
-            var value = expression.GetValue();
+            var value = rightValue ?? expression.GetValue();
+
+            // Check if there are values
             if (value != null)
             {
-                #region Enum
-
+                // Specialized for enum
                 if (expression.Type.IsEnum)
                 {
                     var dbType = TypeMapper.Get(expression.Type);
-                    if (dbType != null && dbType.Value != DbType.String)
-                    {
-                        var mappedToType = new SqlDbTypeToClientTypeResolver().Resolve(dbType.Value);
-                        var convertMethod = typeof(Convert).GetMethod(string.Concat("To", mappedToType.Name), new[] { typeof(object) });
-                        if (convertMethod != null)
-                        {
-                            value = convertMethod.Invoke(null, new[] { value });
-                        }
-                    }
+                    value = Enum.ToObject(expression.Type, value);
                 }
 
-                #endregion
-
+                // Create a new field
                 var field = new QueryField(expression.Member.GetMappedName(), QueryField.GetOperation(expressionType), value);
-                queryGroup = new QueryGroup(field.AsEnumerable());
+
+                // Set the query group
+                queryGroup = new QueryGroup(field);
+
+                // Set the query group IsNot property
                 queryGroup.SetIsNot(isEqualsTo == false);
             }
+
+            // Return the result
             return queryGroup;
         }
 
-        private static QueryGroup Parse<TEntity>(MethodCallExpression expression, bool isNot = false, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup Parse<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo) where TEntity : class
         {
             // Check methods for the 'Like', both 'Array.<All|Any>()'
             if (expression.Method.Name == "All" || expression.Method.Name == "Any")
@@ -858,7 +853,7 @@ private static QueryGroup Parse<TEntity>(MethodCallExpression expression, bool i
             return null;
         }
 
-        private static QueryGroup ParseAllOrAnyForArrayOrAnyForList<TEntity>(MethodCallExpression expression, bool isNot = false, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup ParseAllOrAnyForArrayOrAnyForList<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo) where TEntity : class
         {
             // Return null if there is no any arguments
             if (expression.Arguments?.Any() != true)
@@ -947,7 +942,7 @@ private static QueryGroup ParseAllOrAnyForArrayOrAnyForList<TEntity>(MethodCallE
             return new QueryGroup(queryFields, null, conjunction, (isNot == isEqualsTo));
         }
 
-        private static QueryGroup ParseContainsForArrayOrList<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup ParseContainsForArrayOrList<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo) where TEntity : class
         {
             // Return null if there is no any arguments
             if (expression.Arguments?.Any() != true)
@@ -1004,20 +999,20 @@ private static QueryGroup ParseContainsForArrayOrList<TEntity>(MethodCallExpress
             }
 
             // Add to query fields
-            var operation = isNot ? Operation.NotIn : Operation.In;
+            var operation = (isNot == false && isEqualsTo == true) ? Operation.In : Operation.NotIn;
             var queryField = new QueryField(property.Name, operation, values);
 
             // Return the result
             var queryGroup = new QueryGroup(queryField);
 
             // Set the IsNot value
-            queryGroup.SetIsNot(isEqualsTo == false);
+            queryGroup.SetIsNot(isNot == true && isEqualsTo == false);
 
             // Return the instance
             return queryGroup;
         }
 
-        private static QueryGroup ParseContainsOrStartsWithOrEndsWithForStringProperty<TEntity>(MethodCallExpression expression, bool isNot = false, bool isEqualsTo = true) where TEntity : class
+        private static QueryGroup ParseContainsOrStartsWithOrEndsWithForStringProperty<TEntity>(MethodCallExpression expression, bool isNot, bool isEqualsTo) where TEntity : class
         {
             // Return null if there is no any arguments
             if (expression.Arguments?.Any() != true)