SQL Index Performance - ASC vs DESC

Question

I\'ve got a user table keyed on an auto-increment int column that looks something like this:

CREATE TABLE `user_def` (
  `user_id` int(11) NOT NULL AUTO_INC         


        

Answer 1

From the MySQL 5.6 documentation:

An index_col_name specification can end with ASC or DESC. These keywords are permitted for future extensions for specifying ascending or descending index value storage. Currently, they are parsed but ignored; index values are always stored in ascending order.