<marshall(at)perilith(dot)com> writes:
> Hmmm... Maybe I haven't explained what I'm trying to do clearly.
> I don't wish to insert new fqdn values into this table, only copy
> the contents of one column (`mycol') into another column (`mycol_new').
> Am I missing something here?
Yes. You should be using UPDATE not INSERT, viz
UPDATE mytable SET mycol_new = mycol;
INSERT is for adding new rows.
regards, tom lane