MySQL alter commands

ALTER TABLE users ADD COLUMN mobile VARCHAR(20) UNIQUE;
ALTER TABLE users ADD COLUMN mobile VARCHAR(20) AFTER email UNIQUE;
ALTER TABLE users ADD COLUMN mobile VARCHAR(20) BEFORE email UNIQUE;

ALTER TABLE users
 ADD COLUMN `count` SMALLINT(6) NOT NULL AFTER `lastname`,
 ADD COLUMN `log` VARCHAR(12) NOT NULL AFTER `count`,
 ADD COLUMN `status` INT(10) UNSIGNED NOT NULL AFTER `log`;

ALTER TABLE users CHANGE mobile mobile_no VARCHAR(15) UNIQUE;

ALTER TABLE users DROP COLUMN mobile;