query: PREFIX wikibase: <http://wikiba.se/ontology#>
  PREFIX wd: <http://www.wikidata.org/entity/> 
  PREFIX wdt: <http://www.wikidata.org/prop/direct/>
  PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
  
  SELECT 
  	(GROUP_CONCAT(DISTINCT(?number); separator=", ") as ?numbers) 
  	?player ?playerLabel 
  	(GROUP_CONCAT(DISTINCT(?birthday); separator=", ") as ?date_of_birth) 
  	(GROUP_CONCAT(DISTINCT(?nationalityLabel); separator=", ") as ?nationalities)
  WHERE 
  {
  	wd:Q21011427 wdt:P527 ?player .
  	OPTIONAL { ?player wdt:P569 ?birthday }.
  	OPTIONAL { ?player wdt:P1618 ?number }
  	OPTIONAL { 	?player wdt:P27 ?nationality .
    				?nationality rdfs:label ?nationalityLabel FILTER(lang(?nationalityLabel)="en,en")
  	   		}
  	SERVICE wikibase:label {bd:serviceParam wikibase:language "en,en" }
  }
  GROUP BY ?player ?playerLabel