创建案例的连续日期#

Question

我正在尝试根据客户 ID 和开始和结束日期添加案例#。只要客户的日期范围没有中断，就会应用相同的案例#。见样本数据。有没有办法在 Teradata SQL 中实现这一点？

Answer 1

您可以使用lag() 和累积和获得一个数字：

select t.*,
       sum(case when enddate = prev_enddate + interval '1' day
                then 0 else 1
           end) over (partition by customerid order by startdate
                     ) as result
from (select t.*,
             lag(enddate) over (partition by customerid order by startdate) as prev_enddate
      from t
     ) t;