我有类似的东西
Select A.a, A.b, A.a+A.b as c, (A.a+A.b*2)+A.d as d from Table
但我想知道,如果有可能的话,可以使用这样的东西:
Select A.a,A.b,A.a+A.b as c, (c*2)+A.d as d from Table
谢谢
答案 0 :(得分:3)
不,你做不到,但最好的办法是使用computed column
@pojomx:
如果您不想在查询中保留计算值,则可以使用计算列:
示例:
create table orders
(
product varchar(50) not null,
qty int not null,
unit_price money not null,
amount as qty * unit_price persisted
);
insert into orders(product,qty,unit_price) values('KEYBOARD',5, 20);
select * from orders;
输出:
product qty unit_price amount
KEYBOARD 5 20.00 100.00
答案 1 :(得分:3)
列别名在select的其他列中不可用。您可以使用内联视图重写:
select a, b, c, (c*2)+d as d
from (select A.a, A.b, A.a+A.b as c, A.d as d from Table A) table_alias_for_view
答案 2 :(得分:1)
不在SQL Server中,您必须在第一个示例中执行此操作:
Select A.a, A.b, A.a+A.b as c, (A.a+A.b*2)+A.d as d from Table
或使用派生表,如:
SELECT
dt.a, dt.b,dt.c, dt.c*2+dt.a as d
FROM (Select
A.a, A.b, A.a+A.b as c
from Table
) dt