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 probl

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