PHP / PDO Veri çekmesine rağmen sıfır deği dönüyor?

$userSlot = $dbh->prepare("SELECT * FROM demir_slot WHERE slot_username = :slot_username ORDER BY slot_id ASC");
 $userSlot->execute(array(                      
":slot_username" => $userRow['user_nickname']
));              
$slots = $userSlot->fetch(PDO::FETCH_ASSOC);            
foreach($slots as $slotRow){                  
                     echo '                      
                  <tr>                    
                        <th>'.$slotRow['slot_id'].'</th>    
                                       <td>'.$slotRow['slot_website'].'</td>      
                                      <td><button class="btn btn-success btn-sm" onClick="editSlot("'.$slotRow['slot_hash'].'");">Düzenle</button></td>              
                         </tr>                    
      ';
}

$userRow['user_nickname']

$userRow['user_nickname']

$userQuery = $sth->prepare("SELECT * FROM ****_user WHERE user_nickname = :user_nickname");
$userQuery->execute(array(    ":user_nickname" => $_SESSION['user_nickname']));
$userRow = $userQuery->fetch(PDO::FETCH_ASSOC);