query: #title: Modified single value constraint
  # Complex constraint from [[Property talk:P492]]
  # Lists items having more than one value, except if one of the statements has a [[Property:P4390|mapping relation type&#32;<small dir="ltr">(P4390)</small>]] qualifier, see discusion below. Please don't switch on the normal single value0 constraint, use this instead.
  SELECT DISTINCT ?item ?itemLabel ?count ?sample1  ?sample2  ?exception
  WHERE
  {
  	{
  	SELECT ?item (COUNT(?value) AS ?count) (MIN(?value) AS ?sample1) (MAX(?value) AS ?sample2) {
  			?item wdt:P492 ?value .
              MINUS { 
                ?item p:P492 ?stmt.
                ?stmt pq:P4390 []
              }
  		} GROUP BY ?item HAVING ( ?count > 1 )
  	} .
  	SERVICE wikibase:label { bd:serviceParam wikibase:language "en" } .
  }
  ORDER BY DESC(?count)