如何添加 WHERE 条件以使用 INNER JOIN 进行编码？答案

【问题标题】：How could I add a WHERE condition to code with INNER JOINs?如何添加 WHERE 条件以使用 INNER JOIN 进行编码？
【发布时间】：2019-09-17 10:41:27
【问题描述】：

我不知道如何为 AS 列添加 where 条件，有没有

我尝试过使用方括号的列，但它不起作用

SELECT   
    Suppliers.CompanyName,
    SUM([Order Details].UnitPrice*Quantity) AS [Total sales]
FROM
    [Order Details]  
INNER JOIN 
    Products ON products.ProductID = [Order Details].ProductID
INNER JOIN 
    Suppliers ON Products.SupplierID = Suppliers.SupplierID
WHERE 

GROUP BY 
    Suppliers.CompanyName
ORDER BY 
    2 DESC;

我只想看到总销售额超过 10,000

【问题讨论】：

标签： sql sql-server inner-join where

【解决方案1】：

您需要在 HAVING 子句中添加条件：

SELECT  
  Suppliers.CompanyName, 
  SUM([Order Details].UnitPrice*Quantity)AS [Total sales]
FROM [Order Details] 
INNER JOIN 
Products ON products.ProductID= [Order Details] .ProductID
INNER JOIN
Suppliers ON Products.SupplierID= Suppliers.SupplierID
GROUP BY Suppliers.CompanyName
HAVING SUM([Order Details].UnitPrice*Quantity) > 10000
Order by 2 desc;

【讨论】：

复制/粘贴剩菜，谢谢。

【解决方案2】：

您只需添加HAVING 子句而不是WHERE 子句，

在GROUP BY之后

HAVING SUM([Order Details].UnitPrice*Quantity) > 10000

在您的 SQL 语句中：

SELECT  Suppliers.CompanyName, SUM([Order Details].UnitPrice*Quantity) AS [Total sales]    
  FROM [Order Details]     
 INNER JOIN 
        Products ON products.ProductID= [Order Details] .ProductID
 INNER JOIN
        Suppliers ON Products.SupplierID= Suppliers.SupplierID
GROUP BY Suppliers.CompanyName
HAVING SUM([Order Details].UnitPrice*Quantity) > 10000
ORDER BY 2 desc

【讨论】：