title: Prepared Statement doesn't work
body: <p>So we have a table with all our players and a table for every team. First I get the Id of players playing on this team and then I use said Id in order to get all the information abut this player.
  A friend now told me that I could reduce the server response-time by using prepared statements. But it doesn't work! This is the error message "Fatal error: Call to a member function fetch_assoc() on a non-object in "address" on line 63"</p>
  
  <pre><code>$conn = new mysqli($servername, $username, $password, $dbname);
  if ($conn-&gt;connect_error) {
      die("Connection failed: " . $conn-&gt;connect_error);
  }
  $stmt = $conn-&gt;prepare("SELECT Vorname, Nachname, Bild FROM Spieler WHERE Id IN (?)");
  $stmt-&gt;bind_param("i", $SpielerId);
  $sql1 = "SELECT Id, SpielerId FROM 2Herren";
  $list = $conn-&gt;query($sql1);
  if ($list-&gt;num_rows &gt; 0) {
      while ($rowlist = $list-&gt;fetch_assoc()) {
          $SpielerId = $rowlist["SpielerId"];
  //        $sql2 = "SELECT Vorname, Nachname, Bild FROM Spieler WHERE Id IN ($SpielerId)";
  //        $result = $conn-&gt;query($sql2);
          $result = $stmt-&gt;execute();
          while ($data = $result-&gt;fetch_assoc()) { //Line 63
              echo "&lt;tr&gt;&lt;td&gt;" . $rowlist["Id"] . "&lt;/td&gt;&lt;td&gt;" . $data["Vorname"] . " " . $data["Nachname"] ."&lt;/td&gt;&lt;td&gt;&lt;img style='max-width: 100px; max-heigth: 100px;' src='" . $data["Bild"] . "'&gt;&lt;/td&gt;&lt;/tr&gt;";
          }
      }
  }
  </code></pre>
  
  <p>What's wrong with this code?</p>