stringstream getOfflineHostsQuery;
getOfflineHostsQuery << "SELECT h.id, UNIX_TIMESTAMP(rsv.created_at) AS last_contact "
                        "FROM recentsensorvalues AS rsv "
                        "LEFT JOIN hosts AS h ON rsv.host_id = h.id "
                        "GROUP BY h.id "
                        "ORDER BY rsv.created_at DESC";