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' => , 'type' => ]));

         $limit = ;
         $num = $count / ;//循环多少次
         for ($i = ; $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) {                     $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 += ;
         }
         $message = "处理成功!";
         return $this->splash('success', null, $message);

     }