WITH MR2 AS(
SELECT (SELECT DATE(MIN(MONTHLY),'-1 MONTH') FROM MRR_DATA) AS MONTHLY2
FROM MRR_DATA
UNION
SELECT DATE(MONTHLY2,'+1 MONTH')
FROM MR2
WHERE MONTHLY2 < (SELECT MAX(MONTHLY) FROM MRR_DATA)
)
SELECT
DATE(MONTHLY2,'+1 MONTH') AS 'YM',
IFNULL(
sum(NEW_MRR + EXPANSION_MRR - DOWNGRADE_MRR -CHURN_MRR)
over(ORDER BY MONTHLY),'0') AS MRR
FROM MRR_DATA
RIGHT JOIN MR2
ON MONTHLY = MONTHLY2
GROUP BY 1
ORDER BY 1;