with next_month as (
    select
        strftime(date(max(MONTHLY), '+1 months')) as MONTHLY
    from
        MRR_DATA
),mrr_base as (
    select
        MONTHLY,
        NEW_MRR + EXPANSION_MRR - DOWNGRADE_MRR - CHURN_MRR as MRR
    from
        MRR_DATA
    union all
    select
        MONTHLY,
        0 as MRR
    from
        next_month
)
select
    mb.MONTHLY as YM,
    sum(ifnull(mb2.MRR,0)) as MRR
from
    mrr_base as mb
left join
    mrr_base as mb2
    on mb.MONTHLY > mb2.MONTHLY
group by
    1
order by
    mb.MONTHLY