Sql 在一个月内跟踪客户产品的变化

我需要计算客户在同一个月内为下列产品（语音、数据、短信）进行了多少次传输

下面是一些示例数据

Month        Customer No Product

01/Dec/2012  123         Voice
03/Dec/2012  123         Data
05/Dec/2012  345         Voice
09/Dec/2012  333         Voice
02/Dec/2012  333         data

这是预期的输出

Month   From_Product To_Product Customer_Total

Dec2012 Voice        Data       1
Dec2012 Data         Voice      1

希望这是有意义的

---

关于

您可以使用

lead（）和聚合来处理此问题：

select to_char(month, 'YYYY-MM') as mon, product as from_product, to_product,
       count(*) as customer_total
from (select sd.*,
             lead(product) over (partition by customer, to_char(month, 'YYYY-MM') order by month) as to_product
      from sampledata sd
     ) sd
where to_product is not null
group by to_char(month, 'YYYY-MM');