query: SELECT ?item ?dacs ?mixURL WHERE {
    ?item wdt:P4663 ?dacs .
    FILTER (!regex(?dacs, '-')) .
    OPTIONAL { 
        ?item rdfs:label ?paintername . FILTER (lang(?paintername) = "en") . 
        BIND(CONCAT("[https://tools.wmflabs.org/mix-n-match/#/search/", REPLACE(STR(?paintername), " ", "%20"), " search in Mix'n'match]") AS ?mixURL) . 
    }
   
  }