MySQL Bugs: #1017: Auto-increment column

Bug #1017	Auto-increment column
Submitted:	9 Aug 2003 10:13	Modified:	11 Aug 2003 2:09
Reporter:	[ name withheld ]	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server: InnoDB storage engine	Severity:	S3 (Non-critical)
Version:	4.0.13	OS:	Linux (Linux)
Assigned to:	Heikki Tuuri	CPU Architecture:	Any

Description:
It appears InnoDB can not have an auto-increment column when the 
unique index contains two columns and the auto-increment coumn is the 
second part of the index.

This works fine in MyISAM, but InnoDB returns the error "ERROR 1075: 
Incorrect table definition; There can only be one auto column and it must 
be defined as a key"

How to repeat:
CREATE TABLE `testing` (
  `a` tinyint(4) NOT NULL default '0',
  `b` tinyint(4) NOT NULL auto_increment,
  `c` tinyint(4) NOT NULL default '0',
  PRIMARY KEY  (`a`,`b`)
) TYPE=MyISAM;

Then try changing the type to innodb.

Suggested fix:
I am not sure wether this is a bug or a special case that the manual 
seems to skip over.

If this isn't a bug then it is a feature request.

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.mysql.com/documentation/ and the instructions on
how to report a bug at http://bugs.mysql.com/how-to-report.php

From InnoDB manual as found at: 
http://www.innodb.com/ibman.html

14 Restrictions on InnoDB tables

...

* For an AUTO_INCREMENT column one must always define a key to the table, and that key must contain just the auto-increment column.