$result = mysqli_query($link, $query) or trigger_error(mysqli_error($link));
while($row = mysqli_fetch_row ($result)) {
echo "<tr>";
foreach($row as $i => $value) {
if ($i == 6) {
$value = "<a href='$value'>ссылка</a>";
}
echo "<td>$value</td>";
}
echo "</tr>";
}
echo "</table>";
должно быть
$BD->query('DELETE FROM song WHERE id =?', [$id]);