ERROR 1075 (42000) Incorrect table definition; there can be only one auto column and it must be defi

ERROR 1075 (42000): Incorrect table definition; there can be only one auto column and it must be defined as a key
The table is created as follows:

mysql> create table tb_emp5(
    -> id int(11) not null auto_increment,
    -> name varchar(11),
    -> deptid int(11) not null auto_increment,
    -> salary float,
    -> primary key(id,deptid)
    -> );
ERROR 1075 (42000): Incorrect table definition; there can be only one auto column and it must be defined as a key

when creating a MySQL table, if you want to set auto_increment, you must set the primary key, not null, and only one

After the change is as follows:

mysql> create table tb_emp5(
    -> id int(11) not null auto_increment,
    -> name varchar(11),
    -> deptid int(11) not null,
    -> salary float,
    -> primary key(id)
    -> );

mysql> desc tb_emp5;
+--------+-------------+------+-----+---------+----------------+
| Field  | Type        | Null | Key | Default | Extra          |
+--------+-------------+------+-----+---------+----------------+
| id     | int(11)     | NO   | PRI | NULL    | auto_increment |
| name   | varchar(11) | YES  |     | NULL    |                |
| deptid | int(11)     | NO   |     | NULL    |                |
| salary | float       | YES  |     | NULL    |                |
+--------+-------------+------+-----+---------+----------------+

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