Minor fix

frappe/model/db_query.py

@@ -317,13 +317,14 @@ class DatabaseQuery(object):
 				) and not self.group_by)
 
 			if not group_function_without_group_by:
-
-				args.order_by = "`tab{0}`.`{1}` {2}".format(self.doctype,
-					meta.sort_field or "modified", meta.sort_order or "desc")
+				if args.get("sort_field") and args.get("sort_order"):
+					args.order_by = "`tab{0}`.`{1}` {2}".format(self.doctype,
+						meta.sort_field or "modified", meta.sort_order or "desc")
 
 				# draft docs always on top
 				if meta.is_submittable:
-					args.order_by = "`tab{0}`.docstatus asc, ".format(self.doctype) + args.order_by
+					args.order_by = "`tab{0}`.docstatus asc {1}"\
+						.format(self.doctype, (", " + args.order_by if args.order_by else ""))
 
 	def check_sort_by_table(self, order_by):
 		if "." in order_by: