What is Auto Increment in a Create Table Query in MySQL

The AUTO_INCREMENT=5 in a create table query tells that the first record will start from 5 i.e. not default 1. As we know if you do not set the value to AUTO_INCREMENT then MySQL starts from 1 by default.

The syntax is as follows:

CREATE TABLE yourTableName
(
yourColumnName1 dataType NOT NULL AUTO_INCRMENT,
.
.
.
N,
PRIMARY KEY(yourColumnName1 )
)AUTO_INCREMENT=5;

To understand the above syntax, let us create a table.

Case1 − The table starts auto increment from 1 because it is the default standard.

The query to create a table is as follows:

mysql> create table defaultAutoIncrementDemo
   -> (
   -> Id int NOT NULL AUTO_INCREMENT,
   -> Name varchar(10),
   -> PRIMARY KEY(Id)
   -> );
Query OK, 0 rows affected (2.19 sec)

Now you can insert some records in the table using insert command. The query is as follows:

mysql> insert into defaultAutoIncrementDemo(Name) values('John');
Query OK, 1 row affected (0.23 sec)
mysql> insert into defaultAutoIncrementDemo(Name) values('James');
Query OK, 1 row affected (0.14 sec)
mysql> insert into defaultAutoIncrementDemo(Name) values('Robert');
Query OK, 1 row affected (0.14 sec)
mysql> insert into defaultAutoIncrementDemo(Name) values('Mike');
Query OK, 1 row affected (0.13 sec)

Now you can display all records and check the row will start from 1. The query is as follows:

mysql> select *from defaultAutoIncrementDemo;

The following is the output:

+----+--------+
| Id | Name   |
+----+--------+
|  1 | John   |
|  2 | James  |
|  3 | Robert |
|  4 | Mike   |
+----+--------+
4 rows in set (0.00 sec)

Case2 − Here is the query to start the auto_increment from 5. The query to create a table is as follows:

mysql> create table AutoIncrementStartsFrom5
-> (
-> Id int NOT NULL AUTO_INCREMENT,
-> Name varchar(10),
-> PRIMARY KEY(Id)
-> )AUTO_INCREMENT=5;
Query OK, 0 rows affected (1.00 sec)

Now insert some records in the table using insert command. The query is as follows:

mysql> insert into AutoIncrementStartsFrom5(Name) values('Larry');
Query OK, 1 row affected (0.15 sec)
mysql> insert into AutoIncrementStartsFrom5(Name) values('David');
Query OK, 1 row affected (0.20 sec)
mysql> insert into AutoIncrementStartsFrom5(Name) values('Bob');
Query OK, 1 row affected (0.13 sec)
mysql> insert into AutoIncrementStartsFrom5(Name) values('Ricky');
Query OK, 1 row affected (0.14 sec)

Display all records from the table using select statement. The query is as follows:

mysql> select *from AutoIncrementStartsFrom5;

The following is the output:

+----+-------+
| Id | Name |
+----+-------+
| 5 | Larry |
| 6 | David |
| 7 | Bob   |
| 8 | Ricky |
+----+-------+
4 rows in set (0.00 sec)

Look at the sample output, the auto_increment starts from 5.