sku入库到底是入库那些字段呢？

 /**
     * 组合
     */
    public function combineAttributes(){
        $m_len=count($this->models);
        if($m_len>=2){
            $result=$this->recurse($this->models[$this->index],$this->models[++$this->index],$m_len);
        }else{
            $result=$this->models[0];
        }
       return $result;
    }

    /**
     * 递归拼接属性
     * @param $array1
     * @param $array2
     * @param $m_len
     * @return array
     */
    public function recurse($array1,$array2,$m_len){
        $res=[];
        foreach ($array1 as $a1){
            foreach ($array2 as $a2){
                array_push($res,$a1.','.$a2);
            }
        }
        $this->index++;
        if($this->index<=$m_len-1){
            return $this->recurse($res,$this->models[$this->index],$m_len);
        }else{
            return $res;
        }
    }