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(at)fetter(dot)org http://fetter.org/
phone: +1 510 893 6100 mobile: +1 415 235 3778

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