Re: Boolean to int

From: Arjen van der Meijden <acm(at)tweakers(dot)net>
To: pgsql-sql(at)postgresql(dot)org
Subject: Re: Boolean to int
Date: 2002-07-04 21:32:20
Message-ID: ag2esu$jmb$1@news.tudelft.nl
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How about this hint in the postgresql-manual:

"Tip: Values of the boolean type cannot be cast directly to other
types (e.g., CAST (boolval AS integer) does not work). This can be
accomplished using the CASE expression: CASE WHEN boolval THEN 'value if
true' ELSE 'value if false' END. See also Section 4.12. "

For more information:
http://www.postgresql.org/idocs/index.php?datatype-boolean.html
and
http://www.postgresql.org/idocs/index.php?functions-conditional.html

Stephane Schildknecht wrote:
> Hi,=20
>
> I'd like to get 1 or 0 from a select on a boolean field.=20
>
> How could I do ?
>
> I tried the following rule, which I can't insert :
>
> CREATE FUNCTION bool_to_int( boolean ) RETURNS integer AS '
> DECLARE
> my_bool ALIAS FOR $1 ;
> BEGIN
> -- Retourne 1 si true, 0 si false
> IF my_bool IS FALSE THEN=20
> RETURN 0 ;
> ELSIF my_bool IS TRUE THEN
> RETURN 1 ;
> ELSE RETURN -1 ;
> END IF ;
> END ;
> ' LANGUAGE 'plpgsql';
>
> CREATE RULE boolean_return AS ON SELECT TO DOCUMENT DO INSTEAD
> SELECT=20
> document_id,
> workflow_id,
> type_document_id,
> image_id,
> theme_id,
> document_version,
> document_surtitre,
> document_titre,
> document_chapeau,
> document_synthese,
> document_corps,
> document_pdf,
> document_date_creation,
> document_mot_clef,
> (bool_to_int(document_online)) as document_online,
> bool_to_int(document_valid) as document_valid FROM document;
>
>
> psql:cnambo_proc_stock.sql:69: ERROR: select rule's target entry 15
> has different type from attribute document_online
>
> Who could help me ?
>
> S(at)S
>
> --=20
> _St=E9phane SCHILDKNECHT___________________________________
> | AurorA-SAS 69-71, Av. Pierre Grenier 92100 BOULOGNE |
> | Tel : 01.58.17.03.20 Fax : 01.58.17.03.21 |=20
> | mailto:sschildknecht(at)aurora-linux(dot)com - ICQ : 142504394 |
> | "Free Markets have taught that innovation is best when |=20
> | ideas flow freely." Adam Smith |
> |_________________________________________________________|
>
>
>
>
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