$sql = "SELECT voting_user.*, voting_user_answer.*, voting_answeren.* FROM
voting_user, voting_user_answer, voting_answeren WHERE
voting_user_answer.thema_id = $thema_id AND voting_user.user_id =
voting_user_answer.user_id AND voting_answeren.answer_id =
voting_user_answer.answer_id";

$i=0;
echo "<table border=1>";
echo "<tr><th>answer-ID</th><th>answer</th><th>user</th>";
foreach ($pdo->query($sql) as $row) {


echo "<tr><td>".$row["answer_id"]."</td>
<td>".$row["answer_option"]."</td><td>".$row["user_name"]."
</td></tr>";
$tableRows[$i]=array("answer_option"=>$row["answer_option"],
"user_name"=>$row["user_name"], "cross"=>"x");
$namen[$i]=$row["user_name"];
$answer = Array
(
"answer_option" => $row["answer_option"]
, "test2" => "x"
);


$i++;
$counter=$i-1;
}
echo "</table>";


$resultMatrix = array();

foreach($tableRows as $resulting) {
$from = $resulting['answer_option'];
$to = $resulting['user_name'];
$cross = $resulting['cross'];

$resultMatrix[$from][$to] = $cross;
}

echo '<table border="1">';
echo '<tr>';
echo '<th>', '#', '</th>';


foreach($namen as $user_name) {
echo '<th>', $namen[$i] ,'</th>';
}
echo '</tr>';

foreach(array_keys($resultMatrix) as $answer_option) {
echo '<tr>';
echo '<td>', $answer_option, '</td>';
foreach(array_keys($resultMatrix[$answer_option]) as $user_name) {
echo '<td>', $resultMatrix[$answer_option][$user_name], '</td>';
}

echo '</tr>';
}
echo '</table>';