代码如下：
create database jing_dong charset=utf8;use jing_dong;create table goods(id int unsigned primary key auto_increment not null,name varchar(150) not null,cate_name varchar(40) not null,brand_name varchar(40) not null,price decimal(10,3) not null,is_show bit not null default 1,is_saleoff bit not null default 0);insert into goods values(0,'r510vc 15.6英寸笔记本','笔记本','华硕','3399',default,default);insert into goods values(0,'y400n 14.0英寸笔记本电脑','笔记本','联想','4999',default,default);insert into goods values(0,'g150h 15.6英寸游戏本','游戏本','雷神','8499',default,default);insert into goods values(0,'x550cc 15.6英寸笔记本','笔记本','华硕','2799',default,default);insert into goods values(0,'x240 超级本','超级本','联想','4880',default,default);insert into goods values(0,'u330p 13.3英寸超级本','超级本','联想','4299',default,default);insert into goods values(0,'svp13226scb 触控超级本','超级本','索尼','7999',default,default);insert into goods values(0,'ipad mini 7.9英寸平板电脑','平板电脑','苹果','1998',default,default);insert into goods values(0,'ipad air 9.7英寸平板电脑','平板电脑','苹果','3388',default,default);insert into goods values(0,'ipad mini 配置 retina 显示屏','平板电脑','苹果','2788',default,default);insert into goods values(0,'ideacentre c340 20英寸一体电脑','台式机','联想','3499',default,default);insert into goods values(0,'vostro 3800-r1206 台式电脑','台式机','戴尔','2899',default,default);insert into goods values(0,'imac me086ch/a 21.5英寸一体电脑','台式机','苹果','9188',default,default);insert into goods values(0,'at7-7414lp 台式电脑 linux','台式机','宏碁','3699',default,default);insert into goods values(0,'z220sff f4f06pa工作站','服务站/工作站','惠普','4288',default,default);insert into goods values(0,'poweredge ii服务器','服务器/工作站','戴尔','5388',default,default);insert into goods values(0,'mac pro专业级台式电脑','服务站/工作站','苹果','28888',default,default);insert into goods values(0,'hmz-t3w 头戴显示设备','笔记本配件','索尼','6999',default,default);insert into goods values(0,'商务双肩背包','笔记本配件','索尼','99',default,default);insert into goods values(0,'x3250 m4机架式服务器','服务器/工作站','ibm','6888',default,default);查询语句--查询类型cate_name为超极本的商品名和价格select name,price from goods where cate_name='超级本';--显示商品的分类select distinct cate_name from goods;select cate_name from goods group by cate_name;--求所有电脑产品的平均价格，并且保留两位小数select round(avg(price),2) from goods;--求每种商品的平均价格select cate_name,avg(price) from goods group by cate_name;select cate_name,round(avg(price),2) from goods group by cate_name;--查询每种商品中的最贵，最便宜，平均价，数量select cate_name,max(price),min(price),avg(price),count(*) from goods group by cate_name;--查询所有价格大于平均价格的商品，并按价格降序排序select * from goods where price>(select avg(price) from goods) order by price desc;
