#先登录数据库
mysql -uroot -p
#然后选择数据库
use 数据库
#导入
source 路径名/名字.sql
综合练习
创建商城数据库表结构
#创建用户表
CREATE TABLE USER(
userId INT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(20) NOT NULL,
PASSWORD VARCHAR(18) NOT NULL,
address VARCHAR(100),
phone VARCHAR(11)
);
#一对多的实现
#创建分类表
CREATE TABLE category(
cid VARCHAR(32) PRIMARY KEY ,
cname VARCHAR(100) NOT NULL
#分类名称
);
# 商品表
CREATE TABLE `products` (
`pid` VARCHAR(32) PRIMARY KEY,
`name` VARCHAR(40) ,
`price` DOUBLE(7,2),
category_id VARCHAR(32),
CONSTRAINT FOREIGN KEY(category_id) REFERENCES category(cid)
);
#多对多的实现
#订单表
CREATE TABLE `orders`(
`oid` VARCHAR(32) PRIMARY KEY ,
`totalprice` DOUBLE(12,2),
#总计
`userId` INT,
CONSTRAINT FOREIGN KEY(userId) REFERENCES USER(userId)
#外键
);
#订单项表
CREATE TABLE orderitem(
oid VARCHAR(32),
#订单id
pid VARCHAR(32),
#商品id
num INT ,
#购买商品数量
PRIMARY KEY(oid,pid),
#主键
FOREIGN KEY(oid) REFERENCES orders(oid),
FOREIGN KEY(pid) REFERENCES products(pid)
);
#初始化数据
#用户表添加数据
INSERT INTO USER(username,PASSWORD,address,phone) VALUES('张三','123','北京昌平沙 河','13812345678');
INSERT INTO USER(username,PASSWORD,address,phone) VALUES('王五','5678','北京海 淀','13812345141');
INSERT INTO USER(username,PASSWORD,address,phone) VALUES('赵六','123','北京朝 阳','13812340987');
INSERT INTO USER(username,PASSWORD,address,phone) VALUES('田七','123','北京大 兴','13812345687');
#给分类表初始化数据
INSERT INTO category VALUES('c001','电器');
INSERT INTO category VALUES('c002','服饰');
INSERT INTO category VALUES('c003','化妆品');
INSERT INTO category VALUES('c004','书籍');
#给商品表初始化数据
INSERT INTO products(pid,NAME,price,category_id) VALUES('p001','联想',5000,'c001');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p002','海尔',3000,'c001');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p003','雷神',5000,'c001');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p004','JACK JONES',800,'c002');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p005','真维斯',200,'c002');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p006','花花公子',440,'c002');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p007','劲霸',2000,'c002');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p008','香奈儿',800,'c003');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p009','相宜本草',200,'c003');
INSERT INTO products(pid,NAME,price,category_id) VALUES('p010','梅明子',200,NULL);
#添加订单
INSERT INTO orders VALUES('o6100',18000.50,1);
INSERT INTO orders VALUES('o6101',7200.35,1);
INSERT INTO orders VALUES('o6102',600.00,2);
INSERT INTO orders VALUES('o6103',1300.26,4);
#订单详情表
INSERT INTO orderitem VALUES('o6100','p001',1),('o6100','p002',1),('o6101','p003',1);
多表查询
查询所有用户的订单
SELECT o.oid,o.totalprice,u.userId,u.username
FROM orders o
INNER JOIN
USER u
ON o.userId=u.userId;
查询用户id为1的所有订单详情
SELECT o.oid,o.totalprice,o.userId,u.username,om.pid
FROM orders o
INNER JOIN USER u
ON o.userId=u.userId
INNER JOIN orderitem om
ON o.oid=om.oid
WHERE u.userId=1;
子查询
查看用户为张三的订单
SELECT *
FROM orders
WHERE userId=(
SELECT userId
FROM USER
WHERE username = '张三'
);
查询出订单的价格大于800的所有用户信息
SELECT *
FROM USER
WHERE userId IN(
SELECT DISTINCT userId
FROM
orders
WHERE totalprice>800
);