Set auto increment initial value for MySQL table using ALTER command

To set auto increment initial value for MySQL table, use ALTER command. The first step would be

alter table yourTableName modify yourColumnName int NOT NULL AUTO_INCREMENT PRIMARY KEY,add index(yourColumnName);

The second step is as follows

alter table yourTableName AUTO_INCREMENT=yourStartingValue;

To understand the above syntax, let us create a table. The query to create a table is as follows

mysql> create table setAutoIncrementDemo
   -> (
   -> UserId int,
   -> UserName varchar(20)
   -> );
Query OK, 0 rows affected (0.75 sec)

Now implement the above two steps to set auto increment initial value for MySQL table.

Step 1 -The query is as follows

mysql> alter table setAutoIncrementDemo modify UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY,add index(UserId);
Query OK, 0 rows affected (1.51 sec)
Records: 0 Duplicates: 0 Warnings: 0

Step 2 -The query is as follows

mysql> alter table setAutoIncrementDemo AUTO_INCREMENT=1000;
Query OK, 0 rows affected (0.34 sec)
Records: 0 Duplicates: 0 Warnings: 0

Insert some records in the table using insert command.

The query is as follows

mysql> INSERT INTO setAutoIncrementDemo(UserName) values('John');
Query OK, 1 row affected (0.14 sec)
mysql> INSERT INTO setAutoIncrementDemo(UserName) values('Carol');
Query OK, 1 row affected (0.12 sec)
mysql> INSERT INTO setAutoIncrementDemo(UserName) values('Sam');
Query OK, 1 row affected (0.13 sec)

Display all records from the table using select statement.

The query is as follows

mysql> select *from setAutoIncrementDemo;

The following is the output

+--------+----------+
| UserId | UserName |
+--------+----------+
| 1000   | John     |
| 1001   | Carol    |
| 1002   | Sam      |
+--------+----------+
3 rows in set (0.00 sec)