code: function listQueues()
      {
          try {
  
              $sql = "SELECT `queue_name` FROM `{$this->table}` GROUP BY `queue_name`;";
  
              $stm = $this->conn->prepare($sql);
              $stm->execute();
              $stm->setFetchMode(\PDO::FETCH_ASSOC);
  
              $csr = $stm->fetchAll();
  
  
          } catch (\Exception $e) {
              throw new exReadError('Error While Read From MySql Client.', $e->getCode(), $e);
          }
  
          $list = [];
          foreach ($csr as $item)
              $list[] = $item['queue_name'];
  
          return $list;
      }
docs: Get Queues List
  
  @return string[]
  @throws exIOError