query: #title: WMI code should match a value in P6793
  # Complex constraint from [[Property talk:P6322]]
  #
  SELECT ?item ?value ?wmi
  {
      ?item wdt:P6322 ?value .
      BIND( substr(?value,1,3) as ?wmi )
      MINUS { [] wdt:P6793 ?wmi }
  }