SQL基本语句

关系型数据库中的数据结构：
SERVER > DATABASE > TABLE > ROW > COLUMN

下面以拟建一个数据库为例，列出了一些基本的SQL语句

/*1. 设置SQL语句的编码格式           2. 删除数据库dangdang3. 创建数据库dangdang，指定存储数据所用的编码4. 进入数据库5. 创建表 dd_category(cid, cname, count)6. 添加三行记录，三个书籍分类(10/20/30)7. 查询出所有的书籍分类8. 创建表 dd_book(bid,title,pic,price,pubDate,isOnsale,categoryId)9. 为每种分类添加两三条记录10. 查询出所有的书籍11. 查询出所有的“计算机”类书籍12. 删除10号分类及其下所有的书籍13. 删除编号为6的书籍，需要修改对应分类的书籍数量*/SET NAMES UTF8;DROP DATABASE IF EXISTS dangdang;CREATE DATABASE dangdang CHARSET=UTF8;USE dangdang;CREATE TABLE dd_category(  cid INT PRIMARY KEY,  cname VARCHAR(6),  count INT);INSERT INTO dd_category VALUES(10,'计算机','3'),(20,'美食','3'),(30,'历史','3');SELECT * FROM dd_category;CREATE TABLE dd_book(  bid INT PRIMARY KEY AUTO_INCREMENT,  title VARCHAR(64),  pic VARCHAR(32),  price FLOAT(10,2),  pubDate BIGINT,  isOnsale BOOLEAN,  categoryId INT);INSERT INTO dd_book VALUES(NULL,'javascript高级','img/1.jpg','98.68','123457890123','1',10),(NULL,'html高级','img/2.jpg','98.68','123457890123','1',10),(NULL,'css高级','img/3.jpg','98.68','123457890123','0',10),(NULL,'鱼香肉丝','img/4.jpg','98.68','123457890123','1',20),(NULL,'地锅鲶鱼','img/5.jpg','98.68','123457890123','1',20),(NULL,'老醋花生','img/6.jpg','98.68','123457890123','0',20),(NULL,'丝绸之路','img/7.jpg','98.68','123457890123','1',30),(NULL,'抗日战争','img/8.jpg','98.68','123457890123','0',30),(NULL,'成吉思汗','img/9.jpg','98.68','123457890123','1',30);SELECT * FROM dd_book;SELECT title FROM dd_book WHERE categoryId=(  SELECT cid FROM dd_category WHERE cname='计算机');DELETE FROM dd_category WHERE cid=10;DELETE FROM dd_book WHERE categoryId=10;UPDATE dd_category SET count=count-1 WHERE cid=(  SELECT categoryId FROM dd_book WHERE bid=6);DELETE FROM dd_book WHERE bid=6;