Question

我非常接近这个解决方案，但我只是需要一点帮助才能完成。

我正在尝试获取client_ids的运行计数，无论日期如何，但是我需要日期和ID仍然出现在我的结果中以验证所有内容。

我找到了解决方案here的一部分，但未能根据我的需要对其进行足够的修改。

这是答案应该是什么，依次计算client_ids的出现次数：

id  client_id   deliver_on  running_total
1   138         2017-10-01  1
2   29          2017-10-01  1
3   138         2017-10-01  2
4   29          2013-10-02  2
5   29          2013-10-02  3
6   29          2013-10-03  4
7   138         2013-10-03  3

然而，这是我得到的：

id  client_id   deliver_on  running_total
1   138         2017-10-01  1
2   29          2017-10-01  1
3   138         2017-10-01  1
4   29          2013-10-02  3
5   29          2013-10-02  3
6   29          2013-10-03  1
7   138         2013-10-03  2

代码不计算client_id按顺序显示的次数，而是计算id在上一个日期范围内显示的时间。

这是我的代码，非常感谢任何帮助。

谢谢，

SELECT n.id, n.client_id, n.deliver_on, COUNT(n.client_id) AS "running_total"

FROM orders n 

LEFT JOIN orders o 
    ON (o.client_id = n.client_id 
            AND n.deliver_on > o.deliver_on)          

GROUP BY n.id, n.deliver_on, n.client_id
ORDER BY n.deliver_on ASC

*与答案编辑*

我最终解决了自己的问题。这是带注释的解决方案：

-- Set "1" for counting to be used later

WITH DATA AS (

SELECT

   orders.id, 
   orders.client_id, 
   orders.deliver_on,
   COUNT(1) -- Creates a column of "1" for counting the occurrences

   FROM orders

   GROUP BY 1

   ORDER BY deliver_on, client_id

)

SELECT

   id,
   client_id,
   deliver_on,
   SUM(COUNT) OVER (PARTITION BY client_id 
                           ORDER BY client_id, deliver_on 
                           ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) -- Counts the sequential client_ids based on the number of times they appear

 FROM DATA

Answer 1

只是贴出了回答问题的答案：

-- Set "1" for counting to be used later
WITH DATA AS (

SELECT

   orders.id, 
   orders.client_id, 
   orders.deliver_on,
   COUNT(1) -- Creates a column of "1" for counting the occurrences

   FROM orders

   GROUP BY 1

   ORDER BY deliver_on, client_id

)

SELECT

   id,
   client_id,
   deliver_on,
   SUM(COUNT) OVER (PARTITION BY client_id 
                           ORDER BY client_id, deliver_on 
                           ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) -- Counts the sequential client_ids based on the number of times they appear

 FROM DATA

使用PostgresQL运行计数总计

1 个答案: