insert into MRR_DATA 
values(
(select date(date(max(monthly),'+1 months')) from mrr_data),
0,0,0,0);

with tbl as (
select
    monthly ,
    row_number() over(order by monthly) as row_num,
    NEW_MRR+EXPANSION_MRR-DOWNGRADE_MRR-CHURN_MRR as mrr,
    *
from mrr_data
)
select 
    this.monthly as YM,
    ifnull(SUM(prev.mrr) OVER (ORDER BY this.monthly ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW),0) AS MRR 
from tbl as this 
left join (
select 
    monthly,
    date(date(monthly),'+1 months') as next_month
from mrr_data) as next 
on this.monthly=next.monthly 
left join tbl as prev 
on this.row_num=prev.row_num+1 
order by this.monthly;