Re: SELECT <all fields except "bad_field"> from mytbl;

Or even, slightly shorter:

EXECUTE
'SELECT '
|| array_to_string(ARRAY(
SELECT a.attname
FROM pg_class c, pg_namespace n, pg_attribute a
WHERE n.oid = c.relnamespace
AND a.attrelid = c.oid
AND a.attnum >= 1
AND n.nspname = 'myschema'
AND c.relname = 'mytbl'
AND a.attname <> 'bad_field'
ORDER by a.attnum), ', ')
|| ' FROM myschema.mytbl';

/E