阿里天池龙珠计划SQL训练营课后答案(task01)

CREATE DATABASE aliyuntest;
USE aliyuntest;

-- 1
#创建表格 
CREATE TABLE Addressbook(
	`regist_no` INT NOT NULL PRIMARY KEY,
    `name` VARCHAR(128) NOT NULL,
    `address` VARCHAR(256) NOT NULL,
    `tel_no` CHAR(10),
    `mail_address` CHAR(20)
);

-- 2
#添加列
ALTER TABLE `Addressbook` ADD `postal_code` CHAR(8) NOT NULL;

-- 3
#删除表 
DROP TABLE `Addressbook`;

-- 4
#恢复表格 
CREATE TABLE Addressbook(
	`regist_no` INT NOT NULL PRIMARY KEY,
    `name` VARCHAR(128) NOT NULL,
    `address` VARCHAR(256) NOT NULL,
    `tel_no` CHAR(10),
    `mail_address` CHAR(20),
    `postal_code` CHAR(8) NOT NULL
);