How to alter a MySQL column to be AUTO INCREMENT

Question

I’m trying to modify a table to make its primary key column AUTO_INCREMENT after the fact. I have tried the following SQL, but got a syntax error notification.

ALTER TABLE document
ALTER COLUMN document_id AUTO_INCREMENT

Am I doing something wrong or is this not possible?

Answer 1

Hello @kartik,

Try this:

ALTER TABLE document MODIFY COLUMN document_id INT auto_increment

Hope it helps!!
Thank you!