query: SELECT ?item ?nr_s ?nr_e ?nr_all ?d (GROUP_CONCAT(DISTINCT ?enlabel; SEPARATOR = " ") AS ?enlabels) 
  WHERE 
  {
    ?item (wdt:P31/(wdt:P279*)) wd:Q21191270;
      p:P4908 ?episode_statement.
    ?episode_statement ps:P4908 ?season;
      pq:P1545 ?nr_e.
    ?season p:P179 ?season_statement.
    ?season_statement ps:P179 wd:Q60691083;
      pq:P1545 ?nr_s.
    OPTIONAL {
      ?item p:P179 ?series_statement.
      ?series_statement pq:P1545 ?nr_all.
    }
    OPTIONAL {
      ?item rdfs:label ?enlabel.
      FILTER((LANG(?enlabel)) = "en")
    }
    ?item wdt:P577 ?d . 
    FILTER NOT EXISTS { ?item wdt:P577 ?d2 . FILTER( ?d2 < ?d ) }
  }
  GROUP BY ?item ?nr_s ?nr_e ?nr_all ?d
  ORDER BY (xsd:integer(?nr_s)) (xsd:integer(?nr_e))