我不太清楚派生表的语义，但假设
对于给定月份的新用户，last\u month\u paid=null，并且
next\u month\u paid=null意味着用户在给定的月份有了最后一次付款，我会选择如下方式：

WITH paying_user_stats AS (
    SELECT
        account_id,
        current_month_paid,
        1 as paying_users,
        case when last_month_paid is null then 1 else 0 end as paying_users_new,
        case when next_month_paid is null then 1 else 0 end as paying_users_churn
    FROM accounts
)
SELECT
    current_month_paid,
    sum(paying_users) as paying_users,
    sum(paying_users-paying_users_new) as paying_users_month_begin,
    sum(paying_users-paying_users_churn) as paying_users_month_end,
    sum(paying_users_new) as paying_users_new,
    sum(paying_users_churn) as paying_users_churn
FROM paying_user_stats
GROUP BY current_month_paid

现在，如果我理解了你对保留率的定义，你在寻找 sum(paying_users)/sum(paying_users_month_begin) . 您可能希望在bi工具、电子表格等中的查询之外进行这种划分，以避免意外地将其聚合到未加权平均值等问题。