select p."PartnerArt",p."PartnerBundesland",p."PartnerName",p."VpNr",p."version",p."countryCode", 

       (CASE WHEN array_length(array_agg(qse."ID"),1)=0 THEN '' 

             ELSE  array_to_string(array_agg(qse."ID"),',') END) as "QsEintragsliste",

       'Löschen' as "Löschen", '---' as "Status"

  from "Partner" p

    left outer join "QsEintrag" qse on qse."VpNr"=p."VpNr"

 where qse."ID" is null

 group by p."VpNr"