#### 【例3-1】
* 创建数据库：
CREATE DATABASE chapter03;
* 选择使用数据库chapter03：
USE chapter03;
* 创建student表：
CREATE TABLE student(
id INT(4),
name VARCHAR(20) NOT NULL,
grade FLOAT
);
* 插入一条数据：
INSERT INTO student(id,name,grade)
VALUES(1,'zhangsan',98.5);
* 查询
SELECT * FROM student;
#### 【例3-2】
INSERT INTO student(name,grade,id)
VALUES('lisi',95,2);
* 查询
SELECT * FROM student;
#### 【例3-3】
INSERT INTO student
VALUES(3,'lisi',61.5);
* 查询
SELECT * FROM student;
#### 【例3-4】
INSERT INTO student(id,name)
VALUES(4,'zhaoliu');
* 查询
SELECT * FROM student;
#### 查询表结构
SHOW CREATE TABLE student\G
#### 【例3-5】
INSERT INTO student(id,grade)
VALUES(5,97);
* 查询
SELECT * FROM student;
#### 【例3-6】
INSERT INTO student(grade,name)
VALUES(55,'sunbin');
* 查询
SELECT * FROM student;
#### 【例3-7】
INSERT INTO student
SET id=5,name='boya',grade=99;
* 查询
SELECT * FROM student;
#### 【例3-8】
INSERT INTO student VALUES
(6,'lilei',99),
(7,'hanmeimei',100),
(8,'poly',40.5);
* 查询
SELECT * FROM student;
#### 【例3-9】
INSERT INTO student(id,name) VALUES
(9,'liubei'),(10,'guanyu'),(11,'zhangfei');
* 查询
SELECT * FROM student;
#### 【例3-10】
UPDATE student
set name='caocao',grade=50
WHERE id=1;
* 查询
SELECT * FROM student;
#### 【例3-11】
UPDATE student
SET grade=100
WHERE id<4;
* 查询
SELECT * FROM student;
#### 【例3-12】
UPDATE student
SET grade=80;
* 查询
SELECT * FROM student;
#### 【例3-13】
DELETE FROM student
WHERE id=11;
* 查询
SELECT * FROM student;
#### 【例3-14】
DELETE FROM student
WHERE id>5;
* 查询
SELECT * FROM student;
#### 【例3-15】
DELETE FROM student;
* 查询
SELECT * FROM student;
#### 【例3-16】
* 建库
CREATE TABLE tab_truncate(
id INT(3) PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(4)
);
* 插入数据
INSERT INTO tab_truncate(name)
VALUES('A'),('B'),('C'),('D'),('E');
* 删除记录
TRUNCATE TABLE tab_truncate;
* 查询
SELECT * FROM tab_truncate;
#### 【例3-17】
* 插入数据
INSERT INTO tab_truncate(name)
VALUES('F'),('G'),('H'),('I'),('J');
* 删除
DELETE FROM tab_truncate;
* 插入数据
INSERT INTO tab_truncate(name) VALUES('K');
* 查询
SELECT * FROM tab_truncate;
