| From: | Alvaro Herrera <alvherre(at)dcc(dot)uchile(dot)cl> |
|---|---|
| To: | GUSTAVO MARTIN OCAMPO <gocampo79(at)hotmail(dot)com> |
| Cc: | pgsql-ayuda(at)tlali(dot)iztacala(dot)unam(dot)mx |
| Subject: | Re: [Pgsql-ayuda] indices... |
| Date: | 2003-11-10 17:20:50 |
| Message-ID: | 20031110172050.GE6483@dcc.uchile.cl |
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| Thread: | |
| Lists: | pgsql-es-ayuda |
On Mon, Nov 10, 2003 at 03:22:02PM +0000, GUSTAVO MARTIN OCAMPO wrote:
> Hola lista, tengo una tabla llamada basemovibanco de la forma:
> test=>explain analyze select distinct extract (year from
> basemovibanco.fecha_vencimiento) as fecha;
> Hay alguna manera de optimizar esta consulta?
Hum ... prueba con algo como
CREATE FUNCTION extract_year(date) RETURNS int AS 'return extract(year
from $1);' IMMUTABLE STRICT LANGUAGE sql;
CREATE INDEX bmb_yr_idx ON basemovibanco (extract_year(fecha_vencimiento));
Luego
SELECT distinct extract_year(fecha_vencimiento) as fecha FROM basemovibanco;
etc. Cocinar apropiadamente.
--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
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