Re: Referencing subselect returned value

On Tue, Jan 20, 2004 at 21:21:56 +0100,
Marco Lazzeri <marcomail(at)noze(dot)it> wrote:
> I'd like to reference values returned by a subselect in the same SELECT
> query.
>
> Example:
>
> SELECT id,
> ( SELECT COUNT(*) FROM second ) AS value_to_reference,
> ( value_to_reference + 1 ) AS value_that_uses_referenced_one
> FROM first;
>
> Any suggestions?

If you want to use a subselect repeatedly, you can either repeat it or
join it. Doing a join will normally be better.

Repeated select example:
SELECT id,
( SELECT COUNT(*) FROM second) AS value_to_reference,
( SELECT COUNT(*) FROM second)+1 AS value_to_reference_one,
FROM first;

Join example:
SELECT id,
cnt AS value_to_reference,
cnt+1 AS value_reference_one,
FROM first, (select COUNT(*) AS cnt from second) AS third;