怎么在function里操作pdo呀

如何在function里操作pdo呀
代码如下
require("../inc/pdo.php");

function output($action,$select,$name){
$select=$dbc->prepare("select id,ztname,zttype,zttime,headimg,riseimg from naszt where 1=1 and zttype=:zttype");
$select->bindValue(":zttype",$action);
$select->execute();
$result='';
while($row=$select->fetch()){
$result.='
  • ';
    $result.='
    ';
    $result.='
    ';
    $result.='
      ';
      $result.='
    • 测试1
    • ';
      $result.='
    • 测试12
    ';
    $result.='

    '.$row['ztname'].'

    ';
    $result.=''. $row['zttype'].'';
    $result.='

    1推荐日期:'.$row['zttime'].'

  • ';
    }
    return $result;
    }


header("Content-Type:text/html;charset=utf-8");
$dbtype='mysql';
$host='127.0.0.1';
$dbName='nas';
$user='227227';
$pass='227227';
$db="$dbtype:host=$host;dbname=$dbName";
try{
$dbc=new PDO($db,$user,$pass);
$dbc->exec('SET CHARACTER SET utf8');
$dbc->setAttribute(PDO::ATTR_EMULATE_PREPARES, false); //禁用prepared statements的仿真
}catch(PDOException $e){
echo $e->getMessage();
}
?>


我想在function调用pdo
是不是在pdo里面写class function要继承这个类?

求大神出手指点该如何写!