Re: Query for block updates

Amit Shah <ashah(at)opuspro(dot)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 table
loop
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