sql server alter tablemake field primary key and autoincrement code example

Example 1: 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');

Example 2: id increment ms sql server

CREATE TABLE Persons (
    Personid int IDENTITY(1,1) PRIMARY KEY,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int
);