Question

以下是我的SELECT语句的一小部分：

SELECT CASE WHEN I.IsSimCheckout=1 THEN 
    SUM(DISTINCT SalePrice) ELSE SUM(SalePrice) END 
FROM InvoiceDetail TD WHERE TD.InvoiceID = D.InvoiceID

我想做的是：

SELECT CASE WHEN I.IsSimCheckout=1 THEN 
    SUM(TOP 1 SalePrice ORDER BY SalePrice) + SUM(TOP 1 SalePrice ORDER BY SalePrice DESC) ELSE SUM(SalePrice) END 
FROM InvoiceDetail TD WHERE TD.InvoiceID = D.InvoiceID

显然，我知道后面的SQL不会编译。但基本上，我想要做的是，如果I.IsSimCheckout等于1，那么我想将最高销售价格和最低销售价格加在一起，而不是将所有这些加在一起。希望我想要做的事情有道理并且很明确。

我正在使用SQL Server 2008。

Answer 1

SELECT
.... 
FROM InvoiceDetail TD
OUTER APPLY
(
    SELECT TOP 1 SalePrice
    FROM D(?)
    WHERE TD.InvoiceID = D.InvoiceID
    ORDER BY SalePrice ASC 
) LP
OUTER APPLY
(
    SELECT TOP 1 SalePrice
    FROM D(?)
    WHERE TD.InvoiceID = D.InvoiceID
   ORDER BY SalePrice DESC
) HP
 WHERE TD.InvoiceID = D.InvoiceID

这是一般的想法。我将为您留下SELECT语句。

Answer 2

您可以使用groupby

进行以下操作

  select 
  case when I.IsSimCheckout=1 then max(id.SalePrice)+min(id.SalePrice)
  else sum(id.SalePrice) as result
  from Invoice I join InvoiceDetail ID on I.InvoiceID=Id.InvoiceID
  group by i.InvoiceID, id.InvoiceID, I.IsSimCheckout

试图总结子查询的前1位

2 个答案: