select edit drop-down

<select name="fileselect">
<?php
$pdo = new PDO('mysql:host=localhost;dbname=contisec_portal', 'root', '');
$stmt = $pdo->query("SELECT dateid FROM date_header");
//$stmt = $pdo->execute();
while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
echo "<option value='" . $row['dateid'] . "'>" . $row['dateid'] . "</option>";
}
?>
</select>