SQL 中的“列名无效”错误

Question

这段代码有什么问题？

我得到这个错误：

列名“距离”无效

代码：

SELECT 
    Company.CompanyId as Id,
    ( 6371  * acos( cos( radians(47.8423155) ) * cos( radians( Company.Latitude  ) ) * cos( radians( Company.Longitude  ) - radians(35.232933) ) + sin( radians(47.8423155) ) * sin( radians( Company.Latitude ) ) ) ) AS Distance
FROM 
    Company 
INNER JOIN  
    Product ON Company.CompanyId = Product.CompanyId 
WHERE
    Distance< 5000   
ORDER BY
    Distance

Answer 1

根据您使用的rdbms，某些RDBMS 不允许引用where 和order by 列中的列别名。只需使用实际的列名：

SELECT      Company.CompanyId as Id,
            Company.VisitCount AS myVisitCount 
FROM        Company
INNER JOIN  Product ON  Company.CompanyId = Product.CompanyId 
WHERE       Company.VisitCount < 5000   
ORDER BY    Company.VisitCount

Answer 2

将选择包裹在子选择中

   select * from(SELECT 
    Company.CompanyId as Id,
    ( 6371  * acos( cos( radians(47.8423155) ) * cos( radians( Company.Latitude  ) ) * cos( radians( Company.Longitude  ) - radians(35.232933) ) + sin( radians(47.8423155) ) * sin( radians( Company.Latitude ) ) ) ) AS Distance
FROM 
    Company 
INNER JOIN  
    Product ON (Company.CompanyId = Product.CompanyId) 
) AS P
WHERE
    P.Distance< 5000   
ORDER BY
    P.Distance;

内部子查询返回您使用别名距离进行过滤的函数。