m

app/Http/Controllers/Admin/OrderController.php

@@ -782,6 +782,8 @@ class OrderController extends Controller
 
             if($cost>0){
                 $params['cost'] = $cost;
+            }else{
+                $params['cost'] = null;
             }
             if($logistics_id){
                 $params['logistics_id'] = $logistics_id;