Project(Lateral(BGP( ?s <http://example/p> ?o),
                Slice(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))),
                      0,
                      2)),
        {?label, ?labels, ?o, ?s})