with t as
(
 select
   strftime('%Y-%m', SALES_DATE) as "YEAR_MONTH"
  ,sum(SALES_AMT)  as "MONTH_AMT"
 from
  SALES
 where
  SALES_DATE >= '2023-01-01' and SALES_DATE <= '2023-12-31'
 group by
  "YEAR_MONTH"
)

select
  t1."YEAR_MONTH" as "YEAR_MONTH"
 ,t1."MONTH_AMT" as "MONTH_AMT"
 ,sum(t2."MONTH_AMT") as "CUML_AMT"
from
 t t1
join
 t t2
on
 t1."YEAR_MONTH" >= t2."YEAR_MONTH"
where
 t1."YEAR_MONTH" >= '2023-01' and t1."YEAR_MONTH" <= '2023-12'
group by
 t1."YEAR_MONTH"
order by
 "YEAR_MONTH"
;