Question

Insert sequential number in MySQL?

Answer 1

In MySQL, a sequence is a list of integers generated in the ascending order i.e., 1,2,3… Many applications need sequences to generate unique numbers mainly for identification e.g., customer ID in CRM, employee numbers in HR, and equipment numbers in the services management system.

To create a sequence in MySQL automatically, you set the AUTO_INCREMENT attribute to a column, which typically is a primary key column.

The following rules are applied when you use the AUTO_INCREMENT attribute:

Each table has only one AUTO_INCREMENT column whose data type is typically the integer.

The AUTO_INCREMENT column must be indexed, which means it can be either PRIMARY KEY or UNIQUE index.

The AUTO_INCREMENT column must have a NOT NULL constraint. When you set the AUTO_INCREMENT attribute to a column, MySQL automatically adds the NOT NULL constraint to the column implicitly.