MySQL Orderby a number, Nulls last

Currently, I am doing a very basic OrderBy in my statement. SELECT * FROM tablename WHERE visible=1 ORDER BY position ASC, id DESC The problem with this is that NULL entries for 'position' are treated as 0. Therefore, all entries with position as NULL appear before those with 1,2,3,4. For example, NULL, NULL, NULL, 1, 2, 3, 4 Is there a way to achieve the following ordering? 1, 2, 3, 4, NULL, NULL, NULL.