Question

您好我需要计算按卖家（createdby）分组的子类别= E的客户数量。一旦客户被卖方计算，没有其他卖家应该能够计算该客户，尽管可能存在观察结果。

实施例

id  customerID  CreatedBy   createdate  subcategory
1   1111111111  EVAJEN      2014-03-14  E                                          
2   1111111111  MICMAD      2014-04-15  E
3   9999999999  MICMAD      2014-02-10  E`

由于EVAJEN已经向该客户进行了销售，因此MICMAD不应该计算id = 2。现在我的代码看起来像这样，但我无法检查客户是否已被计算在内。

sel createdby, cast(createdate  as date) as date1, count(distinct customerID)
from MyDatabase
where  subcategory='E' 
group by 1,2`

谢谢

Answer 1

使用子查询获取第一个日期并计算该日期。在大多数数据库（包括Teradata）中，您可以使用窗口函数来获取每个客户的第一行：

select createdby, cast(createdate as date) as date1, count(*)
from (select t.*,
             row_number() over (partition by customerId order by createddate asc) as seqnum 
      from MyDatabase t
      where subcategory = 'E' 
     ) t
where seqnum = 1
group by createdby, cast(createdate as date) ;

Answer 2

您可以使用ROW_NUMBER为每位客户获取一行：

select createdby, cast(createdate as date) as date1, count(*)
from
 (
   select *
   from tab
   where subcategory = 'E' 
   qualify row_number() -- 1st row per customer
           over (partition by customerId 
                 order by createddate) = 1 
     ) t
group by 1,2;

在客户第一次出现时计算客户数量

2 个答案: