CREATE TABLE t1 (id SERIAL);
SHOW CREATE TABLE t1;
CREATE TABLE t2 (id INT SERIAL DEFAULT VALUE);
SHOW CREATE TABLE t2;
CREATE TABLE t3 (id INT UNSIGNED SERIAL DEFAULT VALUE);
SHOW CREATE TABLE t3;
--
CREATE TABLE t4 (id SERIAL, val INT);
SHOW CREATE TABLE t4;
ALTER TABLE t4 ADD INDEX (id, val), DROP INDEX id;
SHOW CREATE TABLE t4;
INSERT INTO t4 VALUES (DEFAULT, 11), (DEFAULT, 22), (1,33), (2,22);
SELECT * FROM t4;