select
   Konto_nach,
   sum(Betrag)* - 1 as Summe 
from
   journal 
   left join
      konten 
      on konten.KontoNr = journal.Konto_nach 
where
   (
      konten.Kontotype = "B"
   )
   and 
   (
      BuchungsJahr = :BJAHR
   )
   and 
   (
      Datum <= :DAT
   )
group by
   Konto_nach 
order by
   Konto_nach