尝试计算总订单数和每月唯一身份客户

Trying to count total orders, and unique monthly customers

我正在尝试获取 30 天时间范围内的订单总量和唯一身份客户的数量。

我有这个table:

order_id, order_date, order_country, customer_id.

(1, '2021/03/04', 'SWE', 1),
(2, '2021/03/01', 'SWE', 1),
(3, '2021/03/01', 'DK', 3),
(4, '2021/03/01', 'DK', 3),
(5, '2021/03/03', 'NOR', 2),
(6, '2021/02/27', 'DK', 3),
(7, '2020/12/30', 'Ger', 4);

我试过这样的事情:

SELECT order_date
     , COUNT(order_id) as orderAmount
     , COUNT(distinct customer_id) as customerAmount 
  FROM orders
 WHERE order_date BETWEEN NOW() - INTERVAL 30 DAY AND NOW() 
 GROUP 
    BY order_date

这就是我想要的每个日期的订单总量。但它只计算每个日期而不是每月的唯一客户,所以同一个客户会出现多次。我尝试了此 sql 脚本的小变体,但无法完全正常工作。

请检查是否是您想要的答案。

架构(MySQL v5.5)

create table orders (order_id int, order_date date, order_country varchar(10), customer_id int);
insert into orders values(1, '2021/03/04', 'SWE', 1);
insert into orders values(2, '2021/03/01', 'SWE', 1);
insert into orders values(3, '2021/03/01', 'DK', 3);
insert into orders values(4, '2021/03/01', 'DK', 3);
insert into orders values(5, '2021/03/03', 'NOR', 2);
insert into orders values(6, '2021/02/27', 'DK', 3);
insert into orders values(7, '2020/12/30', 'Ger', 4);

查询#1

SELECT 
      o.order_date,COUNT(order_id) as orderAmount
     , coalesce(max(Customer_Count),0) as customerAmount 
  FROM orders o left join (select order_date,count(distinct customer_id)Customer_Count from orders o where 
 not exists (select customer_id from orders oa where o.customer_id=oa.customer_id and oa.order_date<o.order_date
            and oa.order_date > now() - INTERVAL 30 DAY  )
 group by order_date) oc on o.order_date=oc.order_date
 WHERE o.order_date BETWEEN NOW() - INTERVAL 30 DAY AND NOW() 
 group by o.order_date
 order by o.order_date;
order_date orderAmount customerAmount
2021-02-27 1 1
2021-03-01 3 1
2021-03-03 1 1
2021-03-04 1 0

View on DB Fiddle

只算客户第一次出现的时间:

SELECT order_date, COUNT(*) as num_orders,
       COUNT(DISTINCT customer_id) as distinct_customers_on_day,
       SUM(SUM(seqnum = 1)) OVER (ORDER BY order_date) as running_distinct_customers
FROM (SELECT o.*, 
             ROW_NUMBER() OVER (PARTITION BY customer_id ORDER BY order_date) as seqnum
      FROM orders o
      WHERE o.order_date BETWEEN NOW() - INTERVAL 30 DAY AND NOW() 
     ) o
GROUP BY order_date;

Here 是一个 db<>fiddle.