When I use the mysql prompt and enter ls<return> I see my mistake, and then press Ctrl+C to abort the command. But of course Ctrl+C actually exists the client...
I'd estimate I make the ctrl-c in mysql about twice a week. Of course, the only reason it's not once a day anymore is because I'm doing less database work.
At this point, it's been years since I used Oracle, but I have problem overriding my old habits.
Oh -- and as of mysql 5.1.10 -- ctrl-C aborts the running query, rather than dumping immediately. (still doesn't fix the problem when you're used to sqlplus and are just trying to clear the command, though).