There are a couple ways you can do this, why do you want to change the database design? If there are many things using this database this might break some of them.
The easy way is to change your SQL statement from select column1, column2 from table; to select column2, column1 from table;
But if you want to change the actual database design then you should check out mySQL ALTER TABLE using this you can ALTER the table design to better fit your needs.