我是一个新手请大家看一下这个sql的语句！

[1127]

create table student(sno char(8)not,null,sname char(10) not null,ssex char(1),sage int check(sage>=14),
sclass char(8),address char(10) primary key(sno) references class(classname)
)
insert into student values('j20001','李楷','m',19,'js2001','北京')
insert into student values('j20002','张会','f'20,'js2001','天津')
insert into student values('j20003','王者','m'20,'js2001','上海')
insert into student values('d20001','赵良','m'18,'dz2001','广洲')
select * from student
select top 2 * from student
select top 60 percent * from student
drop table student

关于sql的为什么我建表的时候出现了错吴，

[nhxqfyb]

not null 多了一个逗号

[happydreamer]

create table student(sno char(8)not null,sname char(10) not null,ssex char(1),sage int check(sage>=14),
sclass char(8),address char(10) primary key(sno) references class(classname)
)
insert into student values('j20001','李楷','m',19,'js2001','北京')
insert into student values('j20002','张会','f',20,'js2001','天津')
insert into student values('j20003','王者','m',20,'js2001','上海')
insert into student values('d20001','赵良','m',18,'dz2001','广洲')
select * from student
select top 2 * from student
select top 60 percent * from student
drop table student

[1127]

大哥们，，你们改的地方我都忙改过了呀！！
可是不行还是有错吴呀这是为什么呀你们试一下！！

[1127]

我把references class(classname)去掉了可以过去，，这是为什么呀？？？？？？？？？

[1127]

谢谢！！大家我知道是什么地方的问题了！