How to realize non-primary key self-growth in mysql

How to achieve non-primary key self-growth in mysql? I believe that many inexperienced people are at a loss about this, so this article summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

Mysql is not only the primary key can grow itself, but the column set as the key can be set to self-growing. As follows:

CREATE TABLE T1 (id INT, col1 INT auto_increment NOT NULL)

The results are as follows:

If you set the col1 column as the key, you can create self-increment.

CREATE TABLE T1 (id INT, col1 INT auto_increment NOT NULL, key (col1))

The results are as follows:

If we set id as the primary key, we can still create it successfully.

CREATE TABLE T2 (id INT PRIMARY KEY, col1 INT auto_increment NOT NULL, key (col1))

The results are as follows:

So the auto-increment column must be a key, but not necessarily a primary key. But can a table have more than one self-increasing column?

A: there can be only one self-increasing column in a table.

CREATE TABLE T3 (id INT PRIMARY KEY auto_increment, col1 INT auto_increment NOT NULL, key (col1))

The results are as follows:

After reading the above, have you mastered how to achieve non-primary key self-growth in mysql? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!