Total number of likes

<?php
try
{
$user = 'root';
$pass = '';
$PDO = new PDO('mysql:host=localhost;dbname=mike', $user, $pass);
$PDO->exec("set names utf8");
$query = "SELECT SUM(likes) as test FROM news WHERE autor=".$_SESSION['id']."";

$c_query = $PDO->prepare($query;
$c_query->execute();
$results = $c_query->fetch(PDO::FETCH_ASSOC);

    if($results)
    {
        echo "Total number of likes: ".$f_test = $results['test'];
    }
}
catch(PDOException $e)
{
echo "Error: " .$e;
}
?>