Как говорится, я просто оставлю это здесь. CREATE TABLE ALLITEMS ( itemid INT ( 10 ) UNSIGNED , itemname VARCHAR ( 50 ) ); ALTER TABLE ALLITEMS CHANGE itemid itemid INT ( 10 ) AUTO_INCREMENT PRIMARY KEY ; DESC ALLITEMS ; INSERT INTO ALLITEMS ( itemname ) VALUES ( 'Apple' ), ( 'Orange' ), ( 'Banana' ); SELECT * FROM ALLITEMS ; I was confused with CHANGE and MODIFY keywords before too : ALTER TABLE ALLITEMS CHANGE itemid itemid INT ( 10 ) AUTO_INCREMENT PRIMARY KEY ; ALTER TABLE ALLITEMS MODIFY itemid INT ( 5 ); While we are there, also note that AUTO_INCREMENT can also start with a predefined number : ALTER TABLE tbl AUTO_INCREMENT = 100; Взято с http://stackoverflow.com/questions/6957370/alter-table-adding-autoincrement-in-mysql