Project(Lateral(BGP( ?s <http://example/p> ?o),
                OrderBy(Project(Extend(Extend(AggregationJoin(Aggregation(??agg1: ?s, SAMPLE,
                                                              {},
                                                              G1=Group((?s),
                                                                 BGP( ?s <http://example/label> ?label))),
                                              Aggregation(??agg2: ?label, GROUP_CONCAT,
                                              {}, G1)),
                                              ?s,
                                              ??agg1),
                                       ?labels,
                                       ??agg2),
                                {?s, ?labels}), (desc (?label)))),
        {?label, ?labels, ?o, ?s})