如何把PHP代码转换为thinkPHP的控制器中

<?php        header('content-type:text/html;charset=utf-8');      mysql_connect('localhost', 'root' ,'');        mysql_select_db("test");         mysql_query("set names utf8");       $querystring = $_post['querystring'];        if(strlen($querystring) >0) {        $sql= "select value from countries where value like '".$querystring."%' limit 10";        $query = mysql_query($sql);            while ($result = mysql_fetch_array($query,mysql_both)){                  $value=$result['value'];             ?>           <li onclick="fill('<?=$value?>')"><?=$value?></li>            <?php           }        }         ?>  

public function query(){      $where = array();      $limit = 10;      if(strlen($queryString)>0){        $where['value'] = array('like','%'.$queryString.'%');      }            $list = M('test')->where($where)->limit($limit)->select();      //todo    }

public function query(){      $where = array();      $limit = 10;      if(strlen($queryString)>0){        $where['value'] = array('like','%'.$queryString.'%');      }            $list = M('countries')->field('value')->where($where)->limit($limit)->select();      //todo    }