SQL处理用户定义列的值

Question

我可以这样做：

SELECT
   1 AS one,
   2 AS two,
   1 + 2 AS three;

但我想这样做：

SELECT
    1 AS one,
    2 AS two,
one + two AS three;

有可能吗？

Answer 1

你可以这样做：

SELECT one, two, (one+two) as three
FROM 
(
    SELECT 
         1 AS one 
         2 AS two
) t;

Answer 2

方法是：

SELECT one, two, one + two AS 'three'
FROM (SELECT 1 as 'one', 2 as 'two') myTable