Teradata SQL: 搜索列中值第一次发生变化

Question

所以，我有一个 table 每天跟踪客户帐户并记录每个工作日的值，例如该帐户的余额。

例如：

Acct_Nbr   Acct_Open_Date   System_Date   Balance
-------------------------------------------------
111        2017-12-01       2017-12-01    0.00
111        2017-12-01       2017-12-04    0.00
111        2017-12-01       2017-12-05    0.00
111        2017-12-01       2017-12-06    500.00
222        2017-12-01       2017-12-01    0.00
222        2017-12-01       2017-12-04    0.00
222        2017-12-01       2017-12-05    0.00
222        2017-12-01       2017-12-06    0.00
222        2017-12-01       2017-12-07    0.00
222        2017-12-01       2017-12-08    250.00

我正在尝试编写一个查询，该查询将 return Acct_Open_Date 和 System_Date 之间的天数，其中余额首次变为 > 0（即帐户获得资金）。

我计划使用 case when 语句（即 <=5 天、6-10 天等）对桶中的天数进行分组，并且对于每个桶 return #帐户数。

根据上面的table，会return:

Time_to_fund   Count_of_accts
-----------------------------
<=5 days       1
6-10 days      1
>10 days       0

我不完全确定如何编写一个查询，该查询将在每个帐户的基础上搜索每一行，直到找到余额 > 0 的值，然后为该行取 System_Date 和从中减去 Acct_Open_Date 得到天数。

如有任何帮助，我们将不胜感激。谢谢！

Answer 1

尝试在 GROUP BY 中使用 GROUP BY：

SELECT CASE WHEN fund_times.Time_to_fund_in_days<= 5 THEN'<=5 days'
when fund_times.Time_to_fund_in_days<= 10 then '6-10 days'
ELSE '>10 days' END as Time_to_fund, COUNT(fund_times.acct_Number) AS Count_of_accts
    (SELECT t.acct_Number, MIN( (t.System_Date - t.Acct_Open_Date) * 86400) as Time_to_fund_in_days
    from table as T
    WHERE t.Balance>0
    GROUP BY t.acct_Number) AS fund_times
GROUP BY CASE WHEN fund_times.Time_to_fund_in_days<= 5 THEN'<=5 days'
when fund_times.Time_to_fund_in_days<= 10 then '6-10 days'
ELSE '>10 days' END

Answer 2

select
   CASE WHEN diff <=  5 THEN'<=5 days'
        when diff <= 10 then '6-10 days'
        ELSE '>10 days'
   END as Time_to_fund,
   COUNT(*)
from
 (
    select
       System_Date - Acct_Open_Date as diff -- number of days between
    from mytable
    where Balance > 0 
    qualify -- find the first row with a Balance > 5
       row_number()
       over (partition by Acct_Nbr
             order by System_Date) = 1
 ) as dt

Teradata SQL: 搜索列中值第一次发生变化

Teradata SQL: Search for the first time a value changes in a column

sql

teradata

gaps-and-islands