本文已参与「新人创作礼」活动，一起开启掘金创作之路。
MySQL是一个关系型数据库管理系统由瑞典MySQL AB公司开发，属于 Oracle旗下产品。MySQL 是最流行的关系型数据库管理系统之一，在 WEB应用方面，MySQL是最好的 RDBMS (Relational Database Management System，关系数据库管理系统) 应用软件之一。
MySQL是一种关系型数据库管理系统，关系数据库将数据保存在不同的表中，而不是将所有数据放在一个大仓库内，这样就增加了速度并提高了灵活性。
MySQL所使用的 SQL 语言是用于访问数据库的最常用标准化语言。MySQL 软件采用了双授权政策，分为社区版和商业版，由于其体积小、速度快、总体拥有成本低，尤其是开放源码这一特点，一般中小型网站的开发都选择 MySQL 作为网站数据库。 #数据库创建
CREATE TABLE books (
id int NOT NULL primary key ,
name varchar(50) default NULL,
author varchar(20) default NULL,
price decimal(11,0) default NULL,
quantity int default '0'
)
INSERT INTO books VALUES ('1', '水浒', '施耐庵', '188', '3');
INSERT INTO books VALUES ('2', '计算机网络', '谢希仁', '49', '3');
INSERT INTO books VALUES ('3', '计算方法', '严蔚敏', '58', '3');
INSERT INTO books VALUES ('4', '计算方法习题集', '殷人昆', '188', '3');
INSERT INTO books VALUES ('5', '数据库技术及应用', '王珊', '38', '3');
INSERT INTO books VALUES ('6', '组合数学', '周伟', '28', '3');
INSERT INTO books VALUES ('7', 'Redis初探', '周旭龙', '25', '3');
CREATE TABLE borrow (
pk int NOT NULL,
cardId int default NULL,
bookId int default NULL,
returnDate date NULL
)
INSERT INTO borrow VALUES ('4', '1', '1', '2017-02-16 00:00:00');
INSERT INTO borrow VALUES ('5', '2', '1', '2017-02-16 00:00:00');
INSERT INTO borrow VALUES ('6', '3', '1', '2016-12-14 11:00:44');
INSERT INTO borrow VALUES ('7', '4', '3', '2016-12-14 11:00:48');
INSERT INTO borrow VALUES ('8', '4', '6', '2016-12-14 11:00:53');
INSERT INTO borrow VALUES ('9', '5', '6', '2016-12-14 11:00:57');
INSERT INTO borrow VALUES ('10', '7', '7', '2016-12-14 11:01:01');
CREATE TABLE cards (
id int NOT NULL,
name varchar(20) default NULL,
class varchar(20) default NULL,
PRIMARY KEY (id)
)
INSERT INTO cards VALUES ('1', '张三', '计科一班');
INSERT INTO cards VALUES ('2', '李四', '计科一班');
INSERT INTO cards VALUES ('3', '王五', '计科二班');
INSERT INTO cards VALUES ('4', '六四', '计科二班');
INSERT INTO cards VALUES ('5', '七七', '软工一班');
INSERT INTO cards VALUES ('6', '粑粑', '软工二班');
CREATE TABLE course (
courseNo int default NULL,
name varchar(20) default NULL,
teacherNo int default NULL
)
INSERT INTO course VALUES ('1', '语文', '1');
INSERT INTO course VALUES ('2', '数学', '2');
INSERT INTO course VALUES ('3', '英语', '3');
INSERT INTO course VALUES ('4', '物理', '4');
CREATE TABLE fruits (
[type] varchar(20) default NULL,
variety varchar(20) default NULL,
price float
)
INSERT INTO fruits VALUES ('apple', 'gala', '2.790');
INSERT INTO fruits VALUES ('apple', 'fuji', '0.240');
INSERT INTO fruits VALUES ('apple', 'limbertwig', '2.870');
INSERT INTO fruits VALUES ('orange', 'valencia', '3.590');
INSERT INTO fruits VALUES ('orange', 'navel', '9.360');
INSERT INTO fruits VALUES ('pear', 'bradford', '6.050');
INSERT INTO fruits VALUES ('pear', 'bartlett', '2.140');
INSERT INTO fruits VALUES ('cherry', 'bing', '2.550');
INSERT INTO fruits VALUES ('cherry', 'chelan', '6.330');
CREATE TABLE score (
StudentNo int default NULL,
CourseNo int default NULL,
score int default NULL
)
INSERT INTO score VALUES ('1', '2', '78');
INSERT INTO score VALUES ('1', '3', '67');
INSERT INTO score VALUES ('1', '4', '67');
INSERT INTO score VALUES ('2', '1', '52');
INSERT INTO score VALUES ('2', '2', '81');
INSERT INTO score VALUES ('2', '3', '92');
INSERT INTO score VALUES ('2', '4', '67');
INSERT INTO score VALUES ('3', '1', '52');
INSERT INTO score VALUES ('3', '2', '47');
INSERT INTO score VALUES ('3', '3', '88');
INSERT INTO score VALUES ('3', '4', '67');
INSERT INTO score VALUES ('4', '2', '88');
INSERT INTO score VALUES ('4', '3', '90');
INSERT INTO score VALUES ('4', '4', '67');
INSERT INTO score VALUES ('5', '1', '52');
INSERT INTO score VALUES ('5', '3', '78');
INSERT INTO score VALUES ('5', '4', '67');
INSERT INTO score VALUES ('6', '1', '52');
INSERT INTO score VALUES ('6', '2', '68');
INSERT INTO score VALUES ('6', '4', '67');
INSERT INTO score VALUES ('1', '1', '52');
INSERT INTO score VALUES ('5', '2', '72');
INSERT INTO score VALUES ('7', '2', '72');
CREATE TABLE student (
name varchar(32) default NULL,
age int default NULL,
sex varchar(8) default NULL,
studentNo int default NULL
)
INSERT INTO student VALUES ('钱二', '19', '女', '2');
INSERT INTO student VALUES ('刘一', '18', '男', '1');
INSERT INTO student VALUES ('张三', '17', '男', '3');
INSERT INTO student VALUES ('李四', '18', '女', '4');
INSERT INTO student VALUES ('王五', '17', '男', '5');
INSERT INTO student VALUES ('赵6', '19', '女', '6');
INSERT INTO student VALUES ('钱二', '25', '男', '7');
CREATE TABLE teacher (
teacherNo int,
name varchar(20) default NULL
)
INSERT INTO teacher VALUES ('1', '叶平');
INSERT INTO teacher VALUES ('2', '贺高');
INSERT INTO teacher VALUES ('3', '杨艳');
INSERT INTO teacher VALUES ('4', '叶平');
