query: SELECT ?item ?nr_s ?nr_e ?nr_all (GROUP_CONCAT(DISTINCT ?enlabel) AS ?enlabels) WHERE {
    ?item wdt:P31/wdt:P279* wd:Q21191270.
    ?season p:P179 ?season_statement.
    ?season_statement ps:P179 wd:Q194213.
    ?season_statement pq:P1545 ?nr_s.
    ?item p:P4908 ?episode_statement.
    ?episode_statement ps:P4908 ?season.
    ?episode_statement pq:P1545 ?nr_e.
    OPTIONAL {
      ?item p:P179 ?series_statement.
      ?series_statement pq:P1545 ?nr_all.
    }
    OPTIONAL {
      ?item rdfs:label ?enlabel.
      FILTER((LANG(?enlabel)) = "en")
    }
  }
  GROUP BY ?item ?nr_s ?nr_e ?nr_all
  ORDER BY xsd:integer(?nr_s) xsd:integer(?nr_e)