query: #Unique value constraint report for P2089: report listing each item
  
  SELECT DISTINCT ?item1 ?item1Label ?item2 ?item2Label ?value 
  {
  	?item1 wdt:P2089 ?value .
  	?item2 wdt:P2089 ?value .
  	FILTER( ?item1 != ?item2 && STR( ?item1 ) < STR( ?item2 ) ) .
  	SERVICE wikibase:label { bd:serviceParam wikibase:language "en" } .
  }
  LIMIT 100