Add Auto-Increment ID to existing table

Question

I already have a database with the columns "fname," "lname," "email," "password," and "ip." I now, however, desire an auto-increment column. Nevertheless, as I enter:

ALTER TABLE users
ADD id int NOT NULL AUTO_INCREMENT

I get the following:

#1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key

Can someone please help me with this?

Answer 1

Try this

ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT;

I hope this helps you.