WITH RECURSIVE M AS (
SELECT
    MIN(MONTHLY) AS min_m,
    MAX(MONTHLY) AS max_m
FROM MRR_DATA
), MONTHS(MONTHLY) AS (
  SELECT min_m FROM M
  UNION
  SELECT date(MONTHLY, '1 month') FROM MONTHS WHERE date(MONTHLY, '1 month') <= (SELECT date(max_m, '1 month') FROM M)
), AD AS (
SELECT
date(MONTHLY, '1 month') MONTHLY,
NEW_MRR + EXPANSION_MRR - DOWNGRADE_MRR - CHURN_MRR TMP
FROM MRR_DATA
)


SELECT
MONTHLY  YM,
SUM(IFNULL(TMP, 0)) OVER (ORDER BY MONTHLY)  MRR
FROM MONTHS
LEFT OUTER JOIN AD USING (MONTHLY)
ORDER BY
MONTHLY