Update exp to sql

Src/Asp.Net/SqlServerTest/Demos/1_Query.cs

@@ -452,6 +452,7 @@ namespace OrmTest.Demo
             var test50 = db.Queryable<Student>().Where(it => it.CreateTime != null).Where(it => SqlFunc.ToDate(it.CreateTime).Year == SqlFunc.GetDate().Year).ToList();
             var test51 = db.Queryable<Student>().Select(it=>new { x= SqlFunc.ToDate(it.CreateTime).Year+"-" }).ToList();
             var test52 = db.Queryable<Student>().Select(it => SqlFunc.IsNull(it.CreateTime, SqlFunc.GetDate())).ToList();
+            var test53 = db.Queryable<Student>().Select(it => SqlFunc.IsNull(it.CreateTime, SqlFunc.GetDate())).First();
         }
         public static void Page()
         {

Src/Asp.Net/SqlSugar/Abstract/SqlBuilderProvider/QueryBuilder.cs

@@ -407,6 +407,10 @@ namespace SqlSugar
             }
             else
             {
+                if (expression is LambdaExpression && (expression as LambdaExpression).Body is MethodCallExpression&&this.Context.CurrentConnectionConfig.DbType==DbType.SqlServer&&this.OrderByValue.HasValue())
+                {
+                    result = result + " AS columnName";
+                }
                 this.SelectCacheKey = result;
                 return result;
             }