$sql = "SELECT * FROM Posts";

$result = $conn->query($sql);

echo "<h1>All</h1>";
echo "<table border='1' width='100%'>";
echo '<tr style="color: red;">';
echo '<td>'. 'id' . '</td><td>' . 'Thread' . '</td><td>' . 'Response' . '</td><td>' . 'Name' . '</td><td>';
echo '</tr>';

while($row = $result->fetch_assoc())
{
    $threadId = $row['Thread'];
    $sql2 = "SELECT * FROM Threads WHERE id=$threadId";

    $result2 = $conn->query($sql2);

    $row2 = $result2->fetch_assoc();
    $thread = $row2['Title'];

    echo '<tr>';
    echo '<td>'. $row['id'] . '</td><td>' . $thread . '</td><td>' . $row['Response'] . '</td><td>' . $row['Name'] . '</rd>';
    echo '</tr>';
}
    echo "</table>";
    ?>