create table staffs(
    id int primary key auto_increment,
    name varchar(24) not null default ‘‘ comment ‘姓名‘,
    age int not null default 0 comment ‘年龄‘,
    pos varchar(20) not null default ‘‘ comment ‘职位‘,
    add_time timestamp not null default current_timestamp comment ‘入职时间‘
    )charset utf8 comment ‘员工记录表‘;



insert into staffs(name,age,pos,add_time) values (‘z3‘,‘22‘,‘manager‘,now());
insert into staffs(name,age,pos,add_time) values (‘z2‘,‘23‘,‘dev‘,now());
insert into staffs(name,age,pos,add_time) values (‘2000‘,‘21‘,‘dev‘,now());
Query OK, 1 row affected (0.15 sec)

alter table staffs add index idx_staffs_nameAgePos(name,age,pos);




mysql> select *from staffs;
+----+------+-----+---------+---------------------+
| id | name | age | pos     | add_time            |
+----+------+-----+---------+---------------------+
|  1 | z3   |  22 | manager | 2019-08-12 23:06:53 |
|  2 | z2   |  23 | dev     | 2019-08-12 23:07:35 |
|  3 | 2000 |  21 | dev     | 2019-08-12 23:07:58 |
+----+------+-----+---------+---------------------+