SELECT A.MONTHLY AS YM
      ,IFNULL((SELECT IFNULL(SUM(X.NEW_MRR), 0) + IFNULL(SUM(X.EXPANSION_MRR), 0) - IFNULL(SUM(X.DOWNGRADE_MRR), 0) - IFNULL(SUM(X.CHURN_MRR), 0) AS MRR
               FROM MRR_DATA X
               WHERE X.MONTHLY < A.MONTHLY
               AND EXISTS (SELECT Y.MONTHLY
                           FROM MRR_DATA Y
                           WHERE DATE(Y.MONTHLY, '-1 months') = DATE(X.MONTHLY))), 0) AS MRR
FROM MRR_DATA A
ORDER BY A.MONTHLY