DROP TABLE IF EXISTS tab_identity;
CREATE TABLE tab_identity(
id INT ,
NAME FLOAT UNIQUE AUTO_INCREMENT,
seat INT 
);
TRUNCATE TABLE tab_identity;
INSERT INTO tab_identity(id,NAME) VALUES(NULL,'john');
INSERT INTO tab_identity(NAME) VALUES('lucy');
SELECT * FROM tab_identity;
SHOW VARIABLES LIKE '%auto_increment%';
SET auto_increment_increment=3;