SQL中的“无效的列名”错误

Question

What's wrong with this code?

I get this error:

Invalid column name 'Distance'

Code:

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

Depending on the rdbms you're using, some RDBMSs don't allow referring to column aliases in the where and order by columns. Just use the actual column names:

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

Wrap the select inside subselect

   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;

The inner subquery returns the function on basis of which you are filtering with the alias Distance.