Re: Postgres and alias

[Stelios Sfakianakis <sgsfak@xxxxxxxxx>]

Hi,

Either:

SELECT description, SUBSTRING( ls_price_and_date, 8, 13) price, SUBSTRING( ls_price_and_date, 21) date
FROM (
    SELECT art.description, f_art_get_price_str( art.id ) ls_price_and_date
    FROM articulos art
) t;

Or use a CTE (which is the exact same thing):

WITH t AS (
    SELECT art.description, f_art_get_price_str( art.id ) ls_price_and_date
    FROM articulos art
)
SELECT description, SUBSTRING( ls_price_and_date, 8, 13) price, SUBSTRING( ls_price_and_date, 21) date
FROM t;

Best,

Stelios

On 28 Aug 2020, at 03:14, Fontana Daniel C (Desartec S.R.L.) <desartecsrl@xxxxxxxxx> wrote:

Perfect.

now let's imagine that '1234567890' is a function f_art_get_price(id_code),
which returns in a string like the following 'XXXZMMM1234567890123yyyy/mm/dd' 
where 1234567890123 is the price and yyyy/mm/dd the date it was last changed price.
How would you do in this case to obtain these values ​​separately?
without calling the function 2 times avoiding overloading the base?

something like this

select art.description,
 f_art_get_price_str( art.id ) as ls_price_and_date
SUBSTRING( ls_price_and_date, 7, 13 )
from articulos;

-----Mensaje original-----
De: Stelios Sfakianakis [mailto:sgsfak@xxxxxxxxx] 
Enviado el: jueves, 27 de agosto de 2020 12:59
Para: Fontana Daniel C (Desartec S.R.L.)
CC: pgsql-general@xxxxxxxxxxxxxxxxxxxx
Asunto: Re: Postgres and alias

Hmm, how about:

SELECT substr (ls_number, 3, 3)
FROM (VALUES('1234567890')) as t(ls_number);

St.

On 27 Aug 2020, at 18:55, Fontana Daniel C (Desartec S.R.L.) <desartecsrl@xxxxxxxxx> wrote:

Hi, I am migrating a database from Sybase to PostgreSql 12.

This select in sybase works for me, but with postgresql it accuses me 
"THERE IS NO COLUMN ls_numero"

select '1234567890' as ls_number,
                substr (ls_number, 3, 3);

Is it possible to get information from an alias in postgresql? how 
would the code be?