WITH SEQ AS (
    SELECT
        min(MONTHLY) as ym
    from
        MRR_DATA
    UNION
    ALL
    SELECT
        date(ym, '+1 months') as ym
    FROM
        SEQ
    WHERE
        date(ym, '+1 months') <= (
            select
                date(max(MONTHLY), '+1 months')
            from
                MRR_DATA
        )
)
select
    ym as YM,
    sum(g) over (
        order by
            ym
    ) MRR
from
    (
        select
            seq.ym,
            ifnull(a.g, 0) g
        from
            seq
            left join (
                select
                    MONTHLY,
                    NEW_MRR + EXPANSION_MRR - DOWNGRADE_MRR - CHURN_MRR as g
                from
                    MRR_DATA
            ) A on seq.ym = DATE(A.MONTHLY, '+1 months')
        order by
            ym
    )