一、名人表

1.查询名人表中性别是男的作者

select * from celebrity where ssex='男'

2.查询静夜思的作者

select celebrity.sname,works.wdynasty,summary.sassess from summary inner join celebrity on summary.sid=celebrity.sid inner join works on summary.wid = works.wid where works.wwork = '静夜思'

3.查询李白和杜甫的年纪

select sage from celebrity where  sname='李白' or sname ='杜甫'

4.查询名人表中男女的个数

  select count(*) from celebrity where ssex='男'
  select count(*) from celebrity where ssex='女'
  select count(*),ssex from celebrity group by ssex having ssex='男' or ssex='女'

5.查询白居易写的作品名称和对于的名句

select celebrity.sname,works.wwork,summary.sassess from summary inner join celebrity on celebrity.sid = summary.sid inner join works on works.wid = summary.wid where celebrity.sname = '白居易'

6.查询年纪在25到30岁之间的个数

select count(*) from celebrity where sage>25 and sage<30

7.查询名人表中最后两条的数据信息

select * from celebrity  LIMIT 4,2;

8.查询李白的作品名称，名句和年纪

select celebrity.sage,works.wwork,summary.sassess from summary inner join celebrity on summary.sid = celebrity.sid inner join works on summary.wid = works.wid where celebrity.sname = '李白'

9.将作品为望岳的朝代修改为北宋

update works set wdynasty = '北宋' where wwork = '望岳'

10.新增名人表中的一个作者王维，年纪25，性别男

insert into celebrity values (7,'王维',29,'男')

二、教师学生表

1.查询sc表中对应何昊老师所教授课程的女生的信息

select s.*,c.cteacher from sc inner join s on sc.sno = s.sno inner join c on sc.cno = c.cno where s.sex = '女' and c.cteacher = '何昊';

2.-- 找出没有选修过何老师的课程的所有学生的姓名

select s.sname from s where not exists( select * from sc,c where sc.cno=c.cno and c.cteacher='何昊' and sc.sno=s.sno);

3.列出有不及格课程（成绩小于60）的学生的姓名

select DISTINCT S.sname from S inner join SC on S.sno = SC.sno where SC.scgrade<60;
select s.sname from s where s.sno not in(select sno from sc where cno =1);

三、商品表

1.查询孙姓用户的个数

select count(*) from user where uname like '孙%'

2.查询年龄最大的两个用户名

select uname from user order by  uage desc limit 0,2;

3.查询张三买的商品名

select product.pname from orders inner join user on orders.ouid = user.uid inner join product on orders.opid = product.pid where user.uname = '张三'

4.查询购买过电脑的用户名

select user.uname from orders inner join `user` on orders.ouid = `user`.uid inner join product on orders.opid = product.pid where product.pname = '电脑'

5.查询订单是909090对应的用户名和商品名

select user.uname,product.pname from orders inner join `user` on orders.ouid = `user`.uid inner join product on orders.opid = product.pid where orders.onumber = 909090

6.查询列表中最高价的前两条数据

select * from product order by pprice desc limit 0,2