满足某些条件时的第一个日期

Question

我试图在条件满足时找到第一个日期。因此，逻辑是如下：

use 
[AdventureWorksDW2012] 
go 

;WITH sales AS (

select  d.OrderDateKey, 
     SalesAmount = SUM(d.SalesAmount) 
from  [dbo].[FactInternetSales] d 
group by d.OrderDateKey 
having  SUM(d.SalesAmount)>10000 
) 

select FirstOrderDateKey = MIN(OrderDateKey) 

from sales 

唯一的问题是，在我的数据是过于复杂和庞大，为每个日期计算的值，然后选择当条件满足时敏时间。当互联网销售额超过10000时，有没有快速找到第一次约会的方法？是否需要某种循环？

Answer 1

你也可以在单个语句中完成。如果您在orderdatekey上有适当的索引，则可以使用此功能提高性能。

select  MIN(s.OrderDateKey) as FirstOrderDateKey 
from  [dbo].[FactInternetSales] d 
group by d.OrderDateKey 
having  SUM(d.SalesAmount)>10000 

Answer 2

SELECT TOP 1 
     d.OrderDateKey 
     ,S.RunningTotal 
FROM [dbo].[FactInternetSales] d 
      CROSS APPLY (SELECT SUM(SalesAmount) AS RunningTotal 
          FROM [dbo].[FactInternetSales] 
          WHERE OrderDateKey <= d.OrderDateKey 
         ) S 
WHERE S.RunningTotal < -- Condition 
ORDER BY d.OrderDateKey DESC