Question

我需要使用TSQL来计算客户交易之间的天数的标准差。该表有两列，CustomerId和TranDate。每位客户至少有3个独特的交易日期。例如，客户abc的交易日期可能是1/1 / 13,1 / 4 / 13,1 / 10/13和1/20/13。交易之间的天数则为3,6和10 - 因此代码应返回客户abc的标准差2.867。

如何按照客户分组的方式对任何数量的交易进行编码？

Answer 1

select id, stdev(DATEDIFF ( dd , '1/1/1900' , enddate ))
from table 
group by id 



with dateOrder as 
(SELECT [fieldID], [value], 
        row_number() over (partition by [fieldID] order by [value]) as row
   FROM [docSVdate])
select do1.fieldID, stdev(datediff(dd, do1.value, do2.value))
  from dateOrder as do1
  join dateOrder as do2
    on do1.fieldID = do2.fieldID 
   and do2.row = do1.row + 1
 group by do1.fieldID

TSQL：交易之间的天数标准差

1 个答案: