Tente isto:
SELECT DATEACCT, PERIOD_ID, STARTDATE, ENDDATE, CREDIT, DEBIT,
SUM (DEBIT-CREDIT) OVER (ORDER BY DATEACCT,PERIOD_ID,STARTDATE,ENDDATE) saldo
from AKUN
ORDER BY DATEACCT, PERIOD_ID, STARTDATE, ENDDATE;
SELECT DATEACCT, PERIOD_ID, STARTDATE, ENDDATE, CREDIT, DEBIT,
SUM (DEBIT-CREDIT) OVER (ORDER BY DATEACCT,PERIOD_ID,STARTDATE,ENDDATE) saldo
from AKUN
ORDER BY DATEACCT, PERIOD_ID, STARTDATE, ENDDATE;