with zengo_tuika as (
          select * from MRR_DATA
    union values
              ((select date(MIN(MONTHLY), '-1 months') FROM MRR_DATA), 0, 0, 0, 0)
            , ((select date(MAX(MONTHLY), '+1 months') FROM MRR_DATA), 0, 0, 0, 0)
)
, yokeina_row_aru as (
    select
          lead(MONTHLY)      over(order by MONTHLY asc) as YM
      ,   sum(NEW_MRR)       over(order by MONTHLY asc)
        + sum(EXPANSION_MRR) over(order by MONTHLY asc)
        - sum(DOWNGRADE_MRR) over(order by MONTHLY asc)
        - sum(CHURN_MRR)     over(order by MONTHLY asc)
        as MRR
    from
        zengo_tuika
    order by
        YM asc
)
select
    YM
  , MRR
from
    yokeina_row_aru
where
    YM is not null
;