<!DOCTYPE html>
<html>
<body>

<?php
echo "<table style='border: solid 1px black;'>";
echo "<tr><th>Id</th><th>Firstname</th><th>Lastname</th></tr>";

class TableRows extends RecursiveIteratorIterator {
     function __construct($it) {
         parent::__construct($it, self::LEAVES_ONLY);
     }

     function current() {
         return "<td style='width: 150px; border: 1px solid black;'>" . parent::current(). "</td>";
     }

     function beginChildren() {
         echo "<tr>";
     }

     function endChildren() {
         echo "</tr>" . "\n";
     }
}

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDBPDO";

try {
     $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
     $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
     $stmt = $conn->prepare("SELECT id, firstname, lastname FROM MyGuests");
     $stmt->execute();

     // set the resulting array to associative
     $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);

     foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) {
         echo $v;
     }
}
catch(PDOException $e) {
     echo "Error: " . $e->getMessage();
}
$conn = null;
echo "</table>";
?>

</body>
</html>