SQL - CASE WHEN 查询

Question

我正在尝试从我的表格中获取为过去 12 个月期间花费超过 1000 的客户开具的所有发票。下面是我的表格，仅供两个客户使用：

我的查询：

SELECT 
    t.Customer, t.Invoice 
FROM 
    (SELECT
         CI.Customer, CI.Invoice, CI.Date,
         SUM(CASE 
                WHEN CI.Date > DATEADD(month, -12, getdate()) 
                   THEN CI.Valuee 
                ELSE 0 
             END) as Net
     FROM 
         CustomerInvoice CI
     GROUP BY 
         CI.Customer, CISRV.Invoice, CISRV.Date) AS t
GROUP BY 
    t.Customer, t.Invoice
HAVING 
   SUM (t.Net) > 1000

因此，我只会收到发票 INV-341453，但我还想显示发票 INV-346218 和 INV-349065。

我做错了什么？

Answer 1

您可以使用分组查询来识别超过 1000 个阈值的客户，然后显示这些客户的所有发票：

SELECT Customer, Invoice 
 FROM CustomerInvoice 
 WHERE Customer IN 
     (SELECT Customer 
     FROM CustomerInvoice
     GROUP BY Customer
     HAVING SUM(CASE WHEN CI.Date>DATEADD(month,-12,getdate()) THEN CI.Valuee ELSE 0 END) > 1000)

Answer 2

使用 ANSI 标准窗口函数：

select ci.*
from (select ci.*,
             sum(ci.value) over (partition by ci.customer) as total_value
      from CustomerInvoice CI
      where CI.Date > DATEADD(month, -12, getdate())
     ) ci
where total_value > 1000;

“所有发票”是指过去 12 个月内的发票。