Specify Default Start Value for Autoiuncrement Column on a non primary key column?

Question

I have a MySQL database table that has many columns. The primary key is PKEY and one of the non primary key column is USERID. This column is set to be autoincrement & it is not a primary key. I would also like to set a default start value of 1000 so that with row insertions it would start incrementing as 1000, 1001, 1002 etc... How can I accomplish this?

Thanks

Answer 1

There can only be one Auto increment column, but it can be any. I'm assuming it's currently your PKEY field, so removing it will mean you need to manually create a unique PKEY to keep it as your primary key.

alter table tablename modify PKEY int(11) unsigned NOT NULL;
alter table  tablename add index (USERID);
alter table  tablename modify USERID int(11) unsigned NOT NULL AUTO_INCREMENT;
ALTER TABLE tablename AUTO_INCREMENT = 1000;

a fresh create would look like this:

CREATE TABLE `foo` (
  `PKEY` int(11) unsigned NOT NULL,
 `USERID` int(11) NOT NULL AUTO_INCREMENT,
 PRIMARY KEY (`PKEY`),
 KEY `USERID` (`USERID`)
) ENGINE=InnoDB  AUTO_INCREMENT = 1000;

However, I'd recommend you make USERID a primary key