Re: ALTER TABLE ( smallinto -> boolean ) ...

On Mon, Aug 29, 2005 at 08:15:41PM -0300, Marc G. Fournier wrote:
> 
> I have a table with several 'smallint' fields that I'd like to convert to 
> booleean ... the data in each is either 0 or 1, and:
> 
> # select '1'::boolean;
>  bool
> ------
>  t
> (1 row)
> # select '0'::boolean;
>  bool
> ------
>  f
> (1 row)
> 
> so they do cast as expected ... but, if I try to do the ALTER, I get:
> 
> # ALTER TABLE table ALTER COLUMN field1 type boolean;
> ERROR:  column "field1" cannot be cast to type "pg_catalog.bool"

> Should this not work?  If not, is there a way to do it so that it will, 
> without having to reload the whole table?

ALTER TABLE "table" ALTER COLUMN field1 TYPE boolean   USING CASE field1 WHEN 0 THEN false ELSE true END;
/* or something to this effect */

HTH :)

Cheers,
D
-- 
David Fetter david@fetter.org http://fetter.org/
phone: +1 510 893 6100   mobile: +1 415 235 3778

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