Re: Simple SQL

Alvaro Herrera wrote:
> On Fri, Oct 24, 2003 at 07:25:44AM +0200, Pavel Stehule wrote:
>
>>Not
>>
>>SELECT 1 as a, a*2;
>>ERROR: column "a" does not exist
>
>
> But you can try
>
> SELECT a, a*a FROM (select 1 as a);
>
>
>>On Tue, 21 Oct 2003, Bob Messenger wrote:
>>
>>
>>>Is it possible to do something like:
>>>
>>> select 1 as a, a*a;
>>>
>>>in postgres?
>
>

alien=# SELECT a, a*a FROM (select 1 as a);
ERROR: sub-SELECT in FROM must have an alias
For example, FROM (SELECT ...) [AS] foo

Thanks for idea though. It led me to this:

alien=# SELECT a, a*a FROM (SELECT 2 AS a) AS a;
a | ?column?
---+----------
2 | 4
(1 row)