MySQL Orderby a number, Nulls last

Question

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. eg:

NULL, NULL, NULL, 1, 2, 3, 4 

Is there a way to achieve the following ordering:

1, 2, 3, 4, NULL, NULL, NULL. 

Answer 1

MySQL has an undocumented syntax to sort nulls last. Place a minus sign (-) before the column name and switch the ASC to DESC:

SELECT * FROM tablename WHERE visible=1 ORDER BY -position DESC, id DESC 

It is essentially the inverse of position DESC placing the NULL values last but otherwise the same as position ASC.

A good reference is here http://troels.arvin.dk/db/rdbms#select-order_by

Answer 2

I found this to be a good solution for the most part:

SELECT * FROM table ORDER BY ISNULL(field), field ASC;