以表本身为参照表的简单有关问题

以表本身为参照表的简单问题
create table Course (Cno char(4) primary key,Cname char(40),Cpno char(4),Ccredit smallint,foreign key Cpno references Course(Cno));


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消息 102，级别 15，状态 1，第 1 行
'Cpno' 附近有语法错误。
该怎么改呢

[解决办法]

SQL code

create table Course (Cno char(4) primary key, Cname char(40), Cpno char(4) constraint fk_cpno foreign key references Course(Cno), Ccredit smallint)
[解决办法]
create table Course (
Cno char(4) primary key,
Cname char(40),
Cpno char(4) references Course(Cno),Ccredit smallint,  
)
[解决办法]
SQL code
create table Course (Cno char(4) primary key,Cname char(40),Cpno char(4),Ccredit smallint,foreign key [color=#FF0000](Cpno)[/color] references Course(Cno));