Add support for .Equals() in SqlExpression's

Author: mythz

src/ServiceStack.OrmLite/Expressions/SqlExpression.cs

@@ -2660,6 +2660,9 @@ protected virtual object VisitColumnAccessMethod(MethodCallExpression m)
                 case "ToLower":
                     statement = $"lower({quotedColName})";
                     break;
+                case "Equals":
+                    statement = $"{quotedColName}={ConvertToParam(wildcardArg)}";
+                    break;                
                 case "StartsWith":
                     statement = !OrmLiteConfig.StripUpperInLike
                         ? $"upper({quotedColName}) like {ConvertToParam(wildcardArg.ToUpper() + "%")}{escapeSuffix}"

tests/ServiceStack.OrmLite.Tests/Expression/StringFunctionTests.cs

@@ -196,6 +196,30 @@ public void Can_select_using_startsWith_with_backtick_in_string()
             }
         }
 
+        [Test]
+        public void Can_select_using_Equals()
+        {
+            var postfix = "postfix";
+
+            var expected = new TestType()
+            {
+                IntColumn = 7,
+                BoolColumn = true,
+                StringColumn = postfix
+            };
+
+            Init(10, expected);
+
+            using (var db = OpenDbConnection())
+            {
+                var actual = db.Select<TestType>(q => q.StringColumn.Equals(postfix));
+
+                Assert.IsNotNull(actual);
+                Assert.AreEqual(1, actual.Count);
+                CollectionAssert.Contains(actual, expected);
+            }
+        }
+
         [Test]
         public void Can_select_using_endsWith()
         {