主键，聚集索引，不是一个东西！

(1) create table user(

         name varchar(10)

)engine=innodb;

(2) insert into user values('shenjian');

(3) insert into user values('shenjian');

A 建表语句(1)报错

B 插入语句(2)报错

C 插入语句(3)报错

D 均不报错

(1) create table user(

         id int,

         name varchar(10),

         primary key(id)

)engine=innodb;

(2) insert into user(name) values('shenjian');

(3) insert into user(name) values('shenjian');

A 建表语句(1)报错

B 插入语句(2)报错

C 插入语句(3)报错

D 均不报错

(1) create table user(

         id int not null,

         name varchar(10) not null,

         primary key(id, name)

)engine=innodb;

(2) insert into user values(1, 'shenjian');

(3) insert into user values(1, 'zhangsan');

(4) insert into user values(2, 'shenjian');

A 建表语句(1)报错

B 插入语句(2)报错

C 插入语句(3)报错

D 插入语句(3)报错

E 均不报错

(1) create table user(

         id int auto_increment,

         name varchar(10) not null,

         primary key(id)

)engine=innodb;

(2) insert into user(name) values('shenjian');

(3) insert into user(id, name) values(10,'shenjian');

(4) insert into user(name) values('shenjian');

A 建表语句(1)报错

B 插入语句(2)报错

C 插入语句(3)报错

D 插入语句(3)报错

E 均不报错

(1) create table user(

         id int auto_increment,

         name varchar(10) not null,

         primary key(name, id)

)engine=innodb;

(2) insert into user(name) values('shenjian');

(3) insert into user(id, name) values(10,'shenjian');

(4) insert into user(name) values('shenjian');

A 建表语句(1)报错

B 插入语句(2)报错

C 插入语句(3)报错

D 插入语句(3)报错

E 均不报错

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【DCEEA】，你答对了吗？

画外音：原文是《主键，五个小习题》，评论里好多同学都答错了，帮转一下吧。