Re: How to reference a subquery column alias?

Hi,

Just wrap your expression with another SELECT and operate with the aliases like

SELECT *, min_caudal + max_caudal AS diferencia FROM (
...your expression...
)

2010/8/9 José María Terry Jiménez <jtj@tssystems.net>:
> Hello
>
> Yesterday a list user solved me a problem with a sententence with two
> subqueries. The solution was this:
>
> SELECT remota_id,min(hora),max(hora), (SELECT caudal FROM historicos WHERE
> remota_id=ooo.remota_id AND hora=min(ooo.hora)) as min_caudal, (SELECT
> caudal FROM historicos WHERE remota_id=ooo.remota_id AND hora=max(ooo.hora))
> as max_caudal from historicos AS ooo GROUP BY remota_id ORDER BY remota_id;
>
> The issue now is i want to do some calculations with the subqueries columns
> (min_caudal and max_caudal), for example adding them. (Get a new column with
> max_caudal and min_caudal (alias) added)
>
> I have tried to add in the SELECT;
> ,max_caudal+min_caudal as diferencia
> ,ooo.max_caudal+ooo.min_caudal as diferencia
> ,historicos.max_caudal+historicos.min_caudal as diferencia
> ,(SELECT max_caudal+min_caudal) as diferencia
>
> I've read the SELECT and Table Expressions documentation pages, but didn't
> found a solution.
>
> Can anyone tell me how to reference or make the calculation with those alias
> names?
>
> TIA
>
> Best,
>
>
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