WITH
MRR AS (
    SELECT
        CURRENT.MONTHLY,
        CURRENT.NEW_MRR,
        CURRENT.EXPANSION_MRR,
        CURRENT.DOWNGRADE_MRR,
        CURRENT.CHURN_MRR,
        IFNULL(PREVIOUS.NEW_MRR + PREVIOUS.EXPANSION_MRR - PREVIOUS.DOWNGRADE_MRR - PREVIOUS.CHURN_MRR, 0) AS MRR
    FROM
        MRR_DATA AS
        CURRENT
    LEFT JOIN
        MRR_DATA AS
        PREVIOUS ON
        PREVIOUS.MONTHLY = DATE(CURRENT.MONTHLY, 'localtime', '-1 month')
)
SELECT
    MRR.MONTHLY AS YM,
    SUM(PAST.MRR) AS MRR
FROM
    MRR
INNER JOIN
    MRR AS
    PAST ON
    PAST.MONTHLY <= MRR.MONTHLY
GROUP BY
    MRR.MONTHLY
ORDER BY
    MRR.MONTHLY ASC