php 循环从数据库分页取数据批量修改数据

 //批量修改email重复
    public function getEmail()
    {
        $this->model = app::get('shop')->model('manage');
        //总条数
        $count = count($this->model->getList('id', [ 'status' => 1, 'type' => 0]));

        $limit = 0;
        $num = $count / 5;//循环多少次
        for ($i = 1; $i <= $num; $i++) {
            $sql = "select * from shop_manage where type = 0 AND status = 1 order by id limit {$limit},5";
            $list = app::get('base')->database()->fetchAll($sql);

            foreach ($list as $k => $v) {16                     $email = $v['email'];

                    $user_id = $v['user_id'];
                   

                    $email = $user_id . '_cfq_' . $email;

                    $result=$this->model->update(['email'=>$email],['user_id'=>$user_id]);

                }

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            $limit += 5;
        }
        $message = "处理成功!";
        return $this->splash('success', null, $message);

    }