For this, use ZEROFILL and alter the table to begin from the same sequence −
alter table yourTableName change yourColumnName yourColumnName int(3) UNSIGNED ZEROFILL NOT NULL AUTO_INCREMENT PRIMARY KEY;
To understand the above syntax, let us first create a table −
mysql> create table DemoTable1958 ( UserId int, UserName varchar(20) ); Query OK, 0 rows affected (0.00 sec)
Here is the query to alter generated sequence number to begin from 001:
mysql> alter table DemoTable1958 change UserId UserId int(3) UNSIGNED ZEROFILL NOT NULL AUTO_INCREMENT PRIMARY KEY; Query OK, 0 rows affected (0.00 sec) Records: 0 Duplicates: 0 Warnings: 0
Let us check the table description:
mysql> desc DemoTable1958;
This will produce the following output −
+----------+--------------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+--------------------------+------+-----+---------+----------------+ | UserId | int(3) unsigned zerofill | NO | PRI | NULL | auto_increment | | UserName | varchar(20) | YES | | NULL | | +----------+--------------------------+------+-----+---------+----------------+ 2 rows in set (0.00 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable1958(UserName) values('Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1958(UserName) values('David'); Query OK, 1 row affected (0.00 sec)
Display all records from the table using select statement −
mysql> select * from DemoTable1958;
This will produce the following output −
+--------+----------+ | UserId | UserName | +--------+----------+ | 001 | Chris | | 002 | David | +--------+----------+ 2 rows in set (0.00 sec)