mysql basic

CREATE TABLE

 CREATE TABLE `critical_url` (
  `id`               INTEGER AUTO_INCREMENT NOT NULL PRIMARY KEY,
  `logical_name`     VARCHAR(100)           NOT NULL,
  `subtype`          VARCHAR(20)            NOT NULL
);

CHANGE COLUMN NAME

ALTER TABLE `critical_urltest`
  CHANGE `gender` `sex` VARCHAR(10) NOT NULL;

ADD COLUMN

ALTER TABLE `critical_urltest`
  ADD COLUMN `last_name` VARCHAR(20) DEFAULT "zhou" NOT NULL;

OR

ALTER TABLE `critical_urltest`
  ADD COLUMN `last_name` VARCHAR(20)  NOT NULL;