Amit Shah <ashah@opuspro.com> writes:
> I am using this query - alter table optiondata ALTER volume TYPE numeric(20,4)
> using cast(volume as numeric(20,4)); then wait for DB to complain, and then
> update that value to null, and just keep doing this till all garbadge is
> removed :-(
You could automate it in plpgsql ... something like
for r in select id, val from tableloop begin perform cast(r.val as numeric(20,4)); exception when
...then update table set val = null where id = r.id; end;end loop;
and then do the ALTER TYPE after you've cleaned the data.
regards, tom lane