Change auto increment starting number?

You can use ALTER TABLE to change the auto_increment initial value:

ALTER TABLE tbl AUTO_INCREMENT = 5;

See the MySQL reference for more details.

How to auto increment by one, starting at 10 in MySQL:

create table foobar(
  id             INT PRIMARY KEY AUTO_INCREMENT,
  moobar         VARCHAR(500)
); 
ALTER TABLE foobar AUTO_INCREMENT=10;

INSERT INTO foobar(moobar) values ("abc");
INSERT INTO foobar(moobar) values ("def");
INSERT INTO foobar(moobar) values ("xyz");

select * from foobar;

'10', 'abc'
'11', 'def'
'12', 'xyz'

This auto increments the id column by one starting at 10.

Auto increment in MySQL by 5, starting at 10:

drop table foobar
create table foobar(
  id             INT PRIMARY KEY AUTO_INCREMENT,
  moobar         VARCHAR(500)
); 
SET @@auto_increment_increment=5;
ALTER TABLE foobar AUTO_INCREMENT=10;

INSERT INTO foobar(moobar) values ("abc");
INSERT INTO foobar(moobar) values ("def");
INSERT INTO foobar(moobar) values ("xyz");

select * from foobar;
'11', 'abc'
'16', 'def'
'21', 'xyz'

This auto increments the id column by 5 each time, starting at 10.

Yes, you can use the ALTER TABLE t AUTO_INCREMENT = 42 statement. However, you need to be aware that this will cause the rebuilding of your entire table, at least with InnoDB and certain MySQL versions. If you have an already existing dataset with millions of rows, it could take a very long time to complete.

In my experience, it's better to do the following:

BEGIN WORK;
-- You may also need to add other mandatory columns and values
INSERT INTO t (id) VALUES (42);
ROLLBACK;

In this way, even if you're rolling back the transaction, MySQL will keep the auto-increment value, and the change will be applied instantly.

You can verify this by issuing a SHOW CREATE TABLE t statement. You should see:

> SHOW CREATE TABLE t \G
*************************** 1. row ***************************
       Table: t
Create Table: CREATE TABLE `t` (
...
) ENGINE=InnoDB AUTO_INCREMENT=43 ...