sql查询如何使用前面的别名

Question

例如：

select (a+b) as c,(d*c) as e ,(f*c) as n from table

我想这样写，但是报错 没有c这个字段，请问大神们怎么解决呢

Answer 1

select c,(d*c) as e ,(f*c) as n from (
select (a+b) as c,d ,f from table) as ll