alter table DT861 add DI040214 float;

update DT861 set 
        di040214  -- Statusbericht: Kosten-Gesamt
        =
        (select sum(DI060601) -- Kosten-Gesamt total
         from DT284
         where DT284.DI060297 = dt861.di023119
         and DT284.DI060300 = (select DI008416 from DT823
                                where DT823.DI008413 = DT861.DI023119
                                and DI029179 = 1)
        );