with rslt as (
    select (select min(monthly) from mrr_data) as YM, 0 as MRR
    union all
    select
        date(ym,'+1 month')
        , mrr+(select new_mrr+expansion_mrr-downgrade_mrr-churn_mrr from mrr_data where monthly=ym) 
    from rslt
    where ym<date((select max(monthly) from mrr_data),('1 month'))
)select * from rslt order by ym asc;