query: #title: Only warning present
  # Complex constraint from [[Property talk:P2758]]
  # [[d:Q23817739|warning <small>(Q23817739)</small>]] needs to be accompanied by a category
  SELECT ?item WHERE { ?item wdt:P2758 wd:Q23817739 . MINUS{ ?item wdt:P2758 ?value . FILTER ( ?value != wd:Q23817739 ) } }