errno：150 报错，学习外键约束的时候，跟着视频敲得一样的代码，为啥我运行不起来

Question

create table s_student(
no int primary key auto_increment,
name varchar(255),
cno int,
foreign key(cno) references t_class(classno));

Answer 1

reate table s_student(
no int primary key auto_increment,
name varchar(255),
cno int,
CONSTRAINT fk_name foreign key(cno) references t_class(classno));