Question

我正在尝试在where子句中使用计算列。

我尝试了从CROSS APPLY到子查询选择的所有内容，但它并没有给我任何接近我需要的东西。

到目前为止我的查询：

SELECT p.Code, c.AccountNumber, Sales = (SUM(p.UnitPrice) * SUM(od.QtyShipped)) FROM [dbo].Customer c 
    LEFT JOIN [dbo].OrderHeader oh ON oh.CustomerId = c.Id 
    LEFT JOIN [dbo].OrderDetail od ON od.OrderHeaderId = oh.Id
    LEFT JOIN [dbo].Product p ON p.Id = od.ProductId
WHERE Sales > 100
GROUP BY p.Code, c.AccountNumber, Sales

这不起作用，因为'Sales'是无效的列

Answer 1

您需要将内部查询包装在派生表或CTE中，以便能够在WHERE子句中使用派生列（另外，注释SUM()仅指定一次，乘法后）：

SELECT x.Code, x.AccountNumber, x.Sales
FROM
(
  SELECT p.Code, c.AccountNumber, SUM(p.UnitPrice *od.QtyShipped) AS Sales 
  FROM [dbo].Customer c 
      LEFT JOIN [dbo].OrderHeader oh ON oh.CustomerId = c.Id 
      LEFT JOIN [dbo].OrderDetail od ON od.OrderHeaderId = oh.Id
      LEFT JOIN [dbo].Product p ON p.Id = od.ProductId
  GROUP BY p.Code, c.AccountNumber
) AS x
WHERE x.Sales > 100;

Answer 2

您可以使用此

的公用表表达式

`;WITH CTE AS
(
SELECT p.Code, c.AccountNumber, Sales = (SUM(p.UnitPrice) * SUM(od.QtyShipped)) FROM [dbo].Customer c 
    LEFT JOIN [dbo].OrderHeader oh ON oh.CustomerId = c.Id 
    LEFT JOIN [dbo].OrderDetail od ON od.OrderHeaderId = oh.Id
    LEFT JOIN [dbo].Product p ON p.Id = od.ProductId

GROUP BY p.Code, c.AccountNumber, Sale

)

SELECT
*
FROM 
CTE WHERE CTE.Sales>100 `

Answer 3

如果是计算列，您可以使用“HAVING”。

SELECT p.Code, c.AccountNumber, Sales = (SUM(p.UnitPrice) * SUM(od.QtyShipped)) FROM [dbo].Customer c 
    LEFT JOIN [dbo].OrderHeader oh ON oh.CustomerId = c.Id 
    LEFT JOIN [dbo].OrderDetail od ON od.OrderHeaderId = oh.Id
    LEFT JOIN [dbo].Product p ON p.Id = od.ProductId
GROUP BY p.Code, c.AccountNumber, Sales
HAVING SALES > 100;

在where子句中使用计算列

3 个答案: