Mysql中order by函数使用

首先创建一个表

create table student(
    id char(36) primary key,
    name varchar(8) not null,
    age int(3) default 0,
    mobile char(11),
    address varchar(150)
);
insert into student 
values ('9b4435ec-372c-456a-b287-e3c5aa23dff4','张三',24,'12345678901','北京海淀');
insert into student 
values ('a273ea66-0a42-48d2-a17b-388a2feea244','李%四',10,'98765432130',null);
insert into student 
values ('eb0a220a-60ae-47b6-9e6d-a901da9fe355','张李三',11,'18338945560','安徽六安');
insert into student 
values ('6ab71673-9502-44ba-8db0-7f625f17a67d','王_五',28,'98765432130','北京朝阳区');
insert into student 
values ('0055d61c-eb51-4696-b2da-506e81c3f566','王_五%%',11,'13856901237','吉林省长春市宽平区');

order by 按序排列

未指明时默认是升序

select * from student order by age #升序
select * from student order by age asc #升序
两者效果相同

降序排序

select * from student order by age desc #降序

在进行多项排序时，先对前者排序，在前者相同时才对后者排序

select * from student order by age desc,mobile #先按age降序排序，当相同时按mobile升序排序
select * from student order by age,mobile desc #先按age升序排序，当相同时按mobile降序排序