Example of using php function to output XML file

$conn= new PDO("mysql:dbname=lamp;host=localhost","root","123456");
$sql="select id,username,phone,*** from user";
$pdo=$conn->prepare($sql);
$pdo->execute();
$str='';
$str.='';
//如果内容中有html代码可以使用
while(list($id,$username,$phone,$***)=$pdo->fetch(PDO::FETCH_NUM)){
    $str.='';
    $str.=''.$username.'';
    $str.=''.$phone.'';
    $str.='<***>'.$***.'';
    $str.='';
}
$str.='';
file_put_contents("user.xml",$str);
header("Content-type:text/xml");
echo $str;
?>