创建数据库

create database if not exists books;

删除数据库

drop database if exists books;

显示所有数据库

show databases;

显示数据库所有表

show tables;

创建数据表

DROP TABLE IF EXISTS `book`;
CREATE TABLE `book` (
  `id` bigint unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(150) DEFAULT NULL COMMENT '名称',
  `price` int DEFAULT '0' COMMENT '价格',
  `author_id` bigint DEFAULT NULL COMMENT '作者',
  `status` tinyint DEFAULT NULL COMMENT '状态',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

显示数据表信息

desc book;

修改表字段

ALTER TABLE `school_info`.`book` 
CHANGE COLUMN `author_id` `author` bigint(0) NULL DEFAULT NULL COMMENT '作者' AFTER `price`;

修改表类型和约束

ALTER TABLE `school_info`.`book` 
MODIFY COLUMN `author` int(4) NULL DEFAULT NULL COMMENT '作者' AFTER `price`;

数据表添加新字段

ALTER TABLE `school_info`.`book` 
ADD COLUMN `create_at` bigint(11) NULL COMMENT '插入日期' AFTER `author`;

数据表删除字段

ALTER TABLE `school_info`.`book` 
DROP COLUMN `update`;

删除数据表

drop table book;