Update exp to sql

Src/Asp.Net/SqlServerTest/UnitTest/UCustom22.cs

@@ -67,6 +67,22 @@ namespace OrmTest
             {
                 throw new Exception("unit error");
             }
+            var list4 = db.Queryable<Order>().Take(10)
+                .Where(it=>$"{it.Id + 1}"=="2").Select(it => new Order
+                {
+                    Name = $"{it.Id + 1}"
+                }).ToList();
+
+            if (list4.Count > 0 && list4.First().Name != "2") 
+            {
+                throw new Exception("unit error");
+            }
+
+            var list5 = db.Queryable<Order>().Take(10)
+               .Select(it => new Order
+              {
+                  Name = SqlFunc.MappingColumn("","id")
+              }).ToList();
         }
 
 

Src/Asp.Net/SqlSugar/ExpressionsToSql/DbMethods/DefaultDbMethod.cs

@@ -512,7 +512,7 @@ namespace SqlSugar
         {
             var str = model.Args[0].MemberValue.ObjToString();
             var array = model.Args.Skip(1).Select(it => it.IsMember?it.MemberName:it.MemberValue).ToArray();
-             return string.Format("'"+str+ "'", array);
+             return string.Format(""+str+ "", array);
         }
 
         public virtual string Abs(MethodCallExpressionModel model)