WITH
    preparedData as (
        SELECT
            userID,
            paymentAmount,
            paymentPeriod,
            paymentDateTime,
            EXTRACT(YEAR_MONTH FROM paymentDateTime) as prepaidPeriodStart,
            EXTRACT(YEAR_MONTH FROM DATE_ADD(paymentDateTime, INTERVAL paymentPeriod MONTH)) as prepaidPeriodEnd
        FROM
            payments
        WHERE
            paymentStatus = 1
            AND paymentPeriod BETWEEN 1 AND 12
            AND userID IS NOT NULL
    ),
    calendar as (
        select
            EXTRACT(YEAR_MONTH FROM paymentDateTime) as reportingYearMonth
        FROM payments
        GROUP BY reportingYearMonth
    )

SELECT
 cal.reportingYearMonth,
 pd.paymentPeriod,
 count(DISTINCT userID) activeUsers
FROM calendar cal
JOIN preparedData pd ON cal.reportingYearMonth BETWEEN pd.prepaidPeriodStart AND prepaidPeriodEnd
GROUP BY
    cal.reportingYearMonth,
    pd.paymentPeriod
ORDER BY reportingYearMonth DESC