连续付款的客户

Question

我不确定这是否可以在 PostgreSQL 上完成，我有一个 table 和 customer_id 和 paid_at（他们付款的月份）我如何找到拥有在过去 6 个月（自 2018 年 1 月起）连续付款，以及自首次付款之日起连续付款的公司 (min(paid_on))?

     customer_id    paid_on
       14535    01/04/2018
       21828    01/10/2017
       52159    01/10/2017
       35033    01/02/2018
       1686     01/08/2016
       7347     01/02/2018
       33721    01/01/2018
       25789    01/07/2017
       62237    01/01/2018
       46184    01/02/2018

Answer 1

示例数据：

create table payments(customer_id int, paid_on date);
insert into payments values
    (1, '2018-03-01'),
    (1, '2018-04-01'),
    (1, '2018-06-01'),
    (1, '2018-07-01'),
    (2, '2018-01-01'),
    (2, '2018-04-01'),
    (2, '2018-05-01'),
    (2, '2018-06-01'),
    (2, '2018-07-01'),
    (3, '2018-03-01'),
    (3, '2018-04-01');

该查询为您提供了最后一次付款的月份和最后一系列连续付款月数以及所有付款月数的信息：

select 
    customer_id, 
    max(paid_on) as last_payment, 
    count(*) filter (where sum = 0) as consecutive_months,
    count(*) as all_months
from (
    select 
        customer_id, paid_on, 
        sum(grp) over w
    from (
        select 
            customer_id, paid_on, 
            (paid_on <> lag((paid_on- '1 month'::interval)::date, 1, paid_on) over w)::int as grp
        from payments
        window w as (partition by customer_id order by paid_on desc)
        ) s
    window w as (partition by customer_id order by paid_on desc)
    ) s
group by 1

 customer_id | last_payment | consecutive_months | all_months 
-------------+--------------+--------------------+------------
           1 | 2018-07-01   |                  2 |          4
           2 | 2018-07-01   |                  4 |          5
           3 | 2018-04-01   |                  2 |          2
(3 rows)

连续付款的客户

customer who have been consecutively paying

sql

postgresql

window-functions