Deleting BLOBs - Mailing list pgsql-general

I'd like to delete all the image files from a table by issuing an
interactive psql command.  Given

CREATE TABLE image (
    name text,
    rast oid
);

with most tuples having images in rast, wanna do something like

=> select lo_unlink('select rast from image');

Can such a thing be done, and how?  I guess I've forgotten the syntax.

Or will an update that sets the oids to null or 0 work?

(pgsql 9.1.2)

Thanks.