WITH
  w_data AS
  (
    SELECT to_date('27.09.2019', 'dd.mm.yyyy') as paydate, 37380 as SumPlan, 37380 as SumFact  FROM dual UNION ALL
    SELECT to_date('17.10.2019', 'dd.mm.yyyy') as paydate, 0 as SumPlan, 37380 as SumFact  FROM dual UNION ALL
    SELECT to_date('27.10.2019', 'dd.mm.yyyy') as paydate, 37380 as SumPlan, 0 as SumFact  FROM dual UNION ALL
    SELECT to_date('21.11.2019', 'dd.mm.yyyy') as paydate, 0 as SumPlan, 37380 as SumFact  FROM dual UNION ALL
    SELECT to_date('26.11.2019', 'dd.mm.yyyy') as paydate, 37380 as SumPlan, 0 as SumFact  FROM dual UNION ALL
    SELECT to_date('26.12.2019', 'dd.mm.yyyy') as paydate, 37380 as SumPlan, 0 as SumFact  FROM dual UNION ALL
    SELECT to_date('25.01.2020', 'dd.mm.yyyy') as paydate, 37380 as SumPlan, 0 as SumFact  FROM dual UNION ALL
    SELECT to_date('24.02.2020', 'dd.mm.yyyy') as paydate, 37380 as SumPlan, 0 as SumFact  FROM dual 
  )
  
SELECT 
  paydate,
  sumplan, 
  sumfact, 
  lag(sumplan-sumfact,1) over (order by paydate) as pastBalance, 
  sumplan + lag(sumplan-sumfact,1) over (order by paydate) as Sumtopay
     
  FROM w_data