4.建表练习

给班级建一个档案表，包括以下信息：

姓名、年龄、email、手机号、简介、毕业薪水、入学日期

姓名：char(3)

年龄：tinyint unsigned

email：varchar(30)

tel：char(11)

intro：varchar(1000)

salary：decimal(7,2)

riqi：date

>create table class(

>id int primary key auto_increment,   #主键不可重复#

>name char(3) not null default '',

>age tinyint unsigned not null default 0,

>email varchar(30) not null default '',

>tel char(11) not null default '',

>salary decimal(7,2) not null default '1800.68',

>riqi date not null default '2012-03-13'

>)charset utf8;

---

增：往哪张表添加？给哪几列添加？分别添加什么值？

>insert into class

>(name,age,email,tel,riqi)    #此行不填默认为所有列#

>values

>('刘备',99,'liubei@shu.com','13801380000','2012-12-26');

---

>insert into class

>values

>(2,'关羽',89,'guanyu@wei.com','12345678910','1234.56','2010-09-07');

---

>insert into class

>(name,age,tel)

>values

>('张飞',79,'110'),('赵云',69,'112'),('黄忠',109,'113'),('马超',59,'114');

---

改：改哪张表？需要改哪几列的值？分别改为什么值？在哪些行生效？

>update class

>set

>email='machao@xiliang.com',salary=3999.34

>where

>id=6;

---

删：要删哪张表的数据？要删哪些行？

>delete from class where name='马超';

查：查哪张表？查哪列？查哪行？

>select * from class;

>select *from class where id<=3;

>select name,tel from class where id =2 ;

>select name from class;