MySQL 8.0

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SELECT month,
       (bal_end - COALESCE(LAG(bal_end) OVER(ORDER BY month), bal_start)) /
       COALESCE(LAG(bal_end) OVER(ORDER BY month), bal_start) AS growth
  FROM (SELECT month,
               MAX(CASE
                     WHEN m_end = 1 THEN
                      sum_balance
                   END) AS bal_end,
               MAX(CASE
                     WHEN m_start = 1 THEN
                      sum_balance
                   END) bal_start
          FROM (SELECT month,
                       SUM(COALESCE(CASE
                                      WHEN bal_start = 1 THEN
                                       balance
                                    END,
                                    0) + COALESCE(revenue, 0)) OVER(ORDER BY date) AS sum_balance,
                       m_end,
                       m_start,
                       date
                  FROM (SELECT DATE_FORMAT(date, '%Y-%m') AS month,
                               t.*,
                               ROW_NUMBER() OVER(PARTITION BY DATE_FORMAT(date, '%Y-%m') ORDER BY date) AS m_start,
                               ROW_NUMBER() OVER(PARTITION BY DATE_FORMAT(date, '%Y-%m') ORDER BY date DESC) AS m_end,
                               ROW_NUMBER() OVER(ORDER BY date) AS bal_start
                          FROM t) AS t0) AS t1
         GROUP BY month) AS t2

month	growth
2021-05	0.2500
2021-06	-0.4000