php 二维数组根据某个字段去重

 $result = array();
        foreach($array as $k=>$val){
            $code = false;
            foreach($result as $_val){
                if($_val['order_id'] == $val['order_id']){
                    $code = true;
                    break;
                }
            }
            if(!$code){
                $result[]=$val;
            }
        }
        return $result;