It's not possible to add

AUTO_INCREMENT

feature to a column that is not selected as a primary key. If we want to add the feature to a column, we must make it primary key

CREATE TABLE note (
    id int AUTO_INCREMENT,
    title varchar(50),
    description varchar(50)
);

After running the above query, the following error will be generated:

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

The correct syntax of the query after adding primary key to the column

id

:

CREATE TABLE note (
    id int AUTO_INCREMENT,
    title varchar(50),
    description varchar(50),
    PRIMARY KEY (id)
);