Personally, I'd use ENUM ... it will probably be faster, takes less space, and best of all, is self-correcting (what if someone enters 'maybe' or '2'? and INT column would accept '2', no complaints. And ENUM column will just set the value to the default value - the first value, if none has been indicated. Because of the way an ENUM column works internally, longer versions (ie., 'yes' and 'no' instead of 'y' and 'n') in an ENUM column will not require more storage space.