Mysql语句

CREATE TABLE user1 (
	id INT PRIMARY KEY NOT NULL COMMENT ‘ID‘,
	NAME VARCHAR(50) COMMENT ‘姓名‘,
	sex VARCHAR(1) COMMENT ‘性别‘,
	age INT COMMENT ‘年龄‘
);

CREATE TABLE user2 (
	id INT NOT NULL COMMENT ‘ID‘,
	NAME VARCHAR(50) COMMENT ‘姓名‘,
	sex VARCHAR(1) COMMENT ‘性别‘,
	age INT COMMENT ‘年龄‘,
	PRIMARY KEY (id)
);

CREATE TABLE user3 (
	id INT NOT NULL COMMENT ‘ID‘,
	NAME VARCHAR(50) COMMENT ‘姓名‘,
	sex VARCHAR(1) COMMENT ‘性别‘,
	age INT COMMENT ‘年龄‘
);
ALTER TABLE user3 ADD PRIMARY KEY(id);

ALTER  TABLE user1 MODIFY COLUMN NAME VARCHAR(60) COMMENT ‘新姓名‘;

ALTER  TABLE user2 CHANGE NAME name1 VARCHAR(60) DEFAULT NULL COMMENT ‘新姓名‘ 

ALTER TABLE user3 RENAME TO user4

CREATE TABLE user5 (
	id INT NOT NULL COMMENT ‘ID‘,
	NAME VARCHAR(50) COMMENT ‘姓名‘,
	sex VARCHAR(1) COMMENT ‘性别‘,
	age INT COMMENT ‘年龄‘
)ENGINE=INNODB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8 COMMENT=‘用户表‘;

ALTER TABLE user5 COMMENT ‘新用户表‘

ALTER TABLE user5 ADD COLUMN tel VARCHAR(50) NOT NULL COMMENT ‘手机号‘ AFTER NAME

ALTER TABLE user5 DROP COLUMN tel ;