mysql Transaction has set autocommit = 0, but still the update happens before I commit

I have multiple mysql InnoDb tables, I am trying to alter/insert/modify many of them in a sql transaction, I set autocommit to false, so that if some sql statements fail, I do commit the rest of statements:

set autocommit = 0;

START TRANSACTION;

use database1;

update table1 set tkey = '3' .....;

update table1 set tkey = '4' .......;

update table1 set tkey = '5' .......;

update table1 set tkey = '6' .......;

ALTER TABLE table2 ADD COLUMN ..... bool NOT NULL; -- This fails

COMMIT;

In above transaction the alter table2 fails, but still the updates to table 1 have happened, how can I avoid that? I want a rolllback even if one statement fails.