sql - 选择一个结果并在另一个选择中使用

Question

我想知道是否有办法做这样的事情。

select outsidecolumn, example1, example2
from (
    select exemple1,example2 
    from tablenames 
    inner joins
    where conditions) as p,
    table2 tb
    where p.example1 = tb.outsidecolumn

Answer 1

我认为这就是你想要的：

select tb.outsidecolumn, p.example1, p.example2
from 
(
  select exemple1,example2 
  from tablenames 
  inner joins
  where conditions
) p
inner join table2 tb
  on p.example1 = tb.outsidecolumn

Answer 2

替代方法 - CTE

并且inner join虽然执行计划可能相同，但也不是笛卡尔坐标系，但可以说更具可读性。

with p as (
    select exemple1,example2 
    from tablenames 
    inner joins
    where conditions
)
select tb.outsidecolumn, p.example1, p.example2
from p
    join table2 tb
    on tb.outsidecolumn = p.example1