ALTER table - adding AUTOINCREMENT in MySQL

Question

I created a table in MySQL with on column itemID.

After creating the table, now I want to change this column to AUTOINCREMENT.

How can this be done using ALTER statements?

Table definition:

ALLITEMS (itemid int(10) unsigned, itemname varchar(50))

I am using the following code but it is throwing a syntax error

Error: syntax incorrect.

ALTER TABLE allitems
MODIFY itemid INT(10) UNSIGNED AUTOINCREMENT;

user_13245882 · Answer

ALTER TABLE employees CHANGE id id int AUTO_INCREMENT PRIMARY KEY;