如何在SQL上通过索引引用字段？

Question

在此SQL查询中：

select
name,
age,
(select sum(something) from sometable where sometable.code = people.code)
from people
where THIRD_COLUMN > 0

如何引用第三列的结果而不必重复SQL？

Answer 1

你做不到。您可以使用子查询并为列命名，但是：

select p.name, p.age, p.THIRD_COLUMN
from (select name, age,
             (select sum(something) from sometable where sometable.code = people.code
             ) as THIRD_COLUMN
      from people
     ) p
where THIRD_COLUMN > 0;

Answer 2

我不知道你使用哪个dms，但在mysql中你可以使用：

select
name,
age,
(select sum(something) from sometable where sometable.code = people.code) sum_people
from people
having sum_people > 0