Re: index on to_char(created, 'YYYY') doesn't work - Mailing list pgsql-sql

From Achilleus Mantzios
Subject Re: index on to_char(created, 'YYYY') doesn't work
Date
Msg-id Pine.LNX.4.44.0301151411490.2448-100000@matrix.gatewaynet.com
Whole thread Raw
In response to Re: index on to_char(created, 'YYYY') doesn't work  (Andreas Joseph Krogh <andreak@officenet.no>)
Responses Re: index on to_char(created, 'YYYY') doesn't work  (Andreas Joseph Krogh <andreak@officenet.no>)
List pgsql-sql
On Wed, 15 Jan 2003, Andreas Joseph Krogh wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Wednesday 15 January 2003 11:37, you wrote:
> > The following does not work:
> >
> > create index session_u_idx on session (to_char(created, 'YYYY'));
> > ERROR:  parser: parse error at or near "'YYYY'" at character 57
> >
> > Can I make a function to do this and index using the result of that
> > funtion? Do anyone have an example of such a function?
>
> I tried the following function:
> - -----------------------------------------------------------------
> create function drus (timestamp) returns varchar AS'
>     DECLARE
>         str_created VARCHAR;
>         created ALIAS FOR $1;
>     BEGIN
>         str_created:= to_char(created, ''YYYY'');
>         RETURN str_created;
>     END;
> ' LANGUAGE 'plpgsql';

add
WITH (iscachable)

>
> create index session_u_idx on session (drus(created));
> - -----------------------------------------------------------------
> But it failes with:
> ERROR:  DefineIndex: index function must be marked isImmutable
>
> Now the question is how do I mark an index function isImmutable?
>
> - --
> Andreas Joseph Krogh <andreak@officenet.no>
>     There will always be someone who agrees with you
>     but is, inexplicably, a moron.
>
> gpg public_key: http://dev.officenet.no/~andreak/public_key.asc
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> DNdajyaQTd27f8MeaWZ+xUE=
> =T3we
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>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>

==================================================================
Achilleus Mantzios
S/W Engineer
IT dept
Dynacom Tankers Mngmt
Nikis 4, Glyfada
Athens 16610
Greece
tel:    +30-10-8981112
fax:    +30-10-8981877
email:  achill@matrix.gatewaynet.com       mantzios@softlab.ece.ntua.gr



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