mysql 习题

习题1

1、创建一个库(dt55_mysql)，在库下创建一张students表
(1)students表中的字段有：id(int类型)，stuName(varchar类型)，age(int类型)，weight(体重，float类型)

(2)往students包中同时插入3条数据

(3)查询students表，为每个字段取一个别名:id(主键)、stuName(学生名字)，age（年龄），weight(体重)

CREATE DATABASE dt55_mysql CHARACTER SET utf8;
CREATE TABLE students(
    id INT,
    stuName VARCHAR(32),
    age INT,
    weight FLOAT
);

INSERT INTO students VALUES (1, 'wang1', 18, 50 ),(2, 'wang2', 18, 50 ),
(3, 'wang3', 18, 50 );

SELECT id AS 主键 ,stuName AS 学生名字, age AS 年龄, weight AS 体重 FROM students;

习题2

create database guan CHARACTER set utf8;
use guan;
create table Book(B_ID int,B_NAME varchar(20),P_ID   INT,B_AUTHOR varchar(20),B_PRICE float);
desc table Book;
alter table Book change B_ID id int;
alter table Book change B_NAME bookname;
alter table Book change B_NAME bookname varchar(20);
alter table Book drop P_ID;
alter table  Book change bookname bookname varchar(40);