php - 如何对整数+字符串值进行排序？

Question

我正在使用 PHP 和 MySQL。

我有 $pallet，它的值如下:

P01  
P02  
P12  
P20  
P05

如何将这些值排序为:

P01  
P02  
P05  
P12  
P20  

Answer 1

如果值始终以“P”开头，那么您可以去掉“P”，将其余部分转换为数字，然后ORDER BY 该数字 ASC。因此:

select yourcolumn 
from (
select cast(replace(yourcolumn,'P','') as unsigned) as rank,
yourcolumn from yourtable) t
order by t.rank asc;

编辑

这是一个按字母顺序排序的例子:

create table pallet (id int unsigned not null primary key auto_increment,
pallet varchar(5));

insert into pallet (pallet) values ('P01');
insert into pallet (pallet) values ('P02');
insert into pallet (pallet) values ('P12');
insert into pallet (pallet) values ('P20');
insert into pallet (pallet) values ('P05');
insert into pallet (pallet) values ('P145');

select * 
from pallet 
order by pallet asc;

结果:

id  pallet
--  ------
1   P01
2   P02
3   P05
4   P12
5   P145
6   P20

不是我们想要的!

select pallet
from (
select cast(replace(pallet,'P','') as unsigned) as rank,
pallet from pallet) t
order by t.rank asc;

结果:

id  pallet
--  ------
1   P01
2   P02
3   P05
4   P12
5   P20
6   P145