consulta sql para calcular a soma e adicionar a soma das linhas anteriores

with t1(  dat_dt, credit, debit) as
(
 select date'2019-02-22',10,  5 from dual union all
 select date'2019-02-25',30, 60 from dual union all
 select date'2019-03-10',50, 40 from dual union all
 select date'2019-03-13',100,10 from dual    
)
select max(dat_dt) as "max date",
       sum(credit) as "cr sum",
       sum(sum(credit)) over ( order by to_char(dat_dt,'yyyymm') ) as "progressive credit", 
       sum(debit) as "dr sum",
       sum(sum(debit))  over ( order by to_char(dat_dt,'yyyymm') ) as "progressive debit"
  from t1
 group by to_char(dat_dt,'yyyymm')
 order by to_char(dat_dt,'yyyymm');