sql auto increment column code example

Example 1: sql query to make a existing column auto increment

Alter table table_name modify column_name datatype(length) AUTO_INCREMENT PRIMARY KEY

Example 2: what is auto increment in sql

Autoincrement keyword allows the
user to create a unique number to get
generated whenever a new record is
inserted into the table.
This keyword is usually required 
whenever PRIMARY KEY in SQL is used.

Example 3: how to auto increment in sql

CREATE TABLE Persons (
    Personid int NOT NULL AUTO_INCREMENT,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    PRIMARY KEY (Personid)
);
INSERT INTO Persons (FirstName,LastName)
VALUES ('Lars','Monsen');

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Sql Example