Is possible to do a ROLLBACK in a MySQL trigger?

Question

Just that is the question: is possible to do a ROLLBACK in a MySQL trigger?

If answer is yes, then, please, explain how.

Answer 1

From: http://dev.mysql.com/doc/refman/5.1/en/trigger-syntax.html

The trigger cannot use statements that explicitly or implicitly begin or end a transaction such as START TRANSACTION, COMMIT, or ROLLBACK.

and

For transactional tables, failure of a statement should cause rollback of all changes performed by the statement. Failure of a trigger causes the statement to fail, so trigger failure also causes rollback. For nontransactional tables, such rollback cannot be done, so although the statement fails, any changes performed prior to the point of the error remain in effect.