PHP (Daten auslesen / Button)

<?php 
                                                $sql = "SELECT * FROM wimbit16a WHERE kat = 'mathe' ORDER BY RAND() LIMIT 1";
                                                foreach ($pdo->query($sql) as $row) {
                                                ?>
    <div class="col-md-12">
      <div class="panel panel-default">


        <div class="panel-title">
          Frage
        </div>
        <div class="panel-heading">
                                                <?php 
                                                    echo $row['frage'];
                                                ?>
        </div>


      </div>
    </div>
    </div>
    <div class="row">
    <div class="col-md-12">
      <div class="panel panel-danger">


        <div class="panel-title">
          Antwort
        </div><br>


        <div class="panel-body">
          <?php echo $row["antwort"]; ?>
        </div>
          <?php } ?>