text: delete from channels where server_id=:server_id: and channel_id in (:channel_id:);
  delete from channel_properties where server_id=:server_id: and id in (:channel_id:);
  delete from group_channel_to_client where server_id=:server_id: and id2 in (:channel_id:);
  delete from perm_channel where server_id=:server_id: and id1 in (:channel_id:);
  delete from perm_channel_clients where server_id=:server_id: and id1 in (:channel_id:);
  delete from tokens where token_type=1 and token_id2 in (:channel_id:);