Ok, so this is definitely caused by some earlier modification. So, you'll need to run a couple of queries.

alter table ubbt_ONLINE drop ONLINE_REFER

then

alter table ubbt_ONLINE
change ONLINE_AGENT ONLINE_AGENT varchar(255),
add ONLINE_REFERER varchar(255)


You could probably do those in the same query, but we'll keep them separate just to make things a bit easier to follow what's happening.