如何排序整数+字符串值？

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

他们都以P开头吗？如果是这样，您可以sort($pallet)或执行ORDER BY yourcolumnhere ASC，因为按字母顺序对它们进行排序就足够了。

Answer 2

如果值始终以'P'开头，则可以去除'P'，将其余部分转换为数字，然后将ORDER BY转换为ASC。因此：

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

修改

以下是按字母顺序排序的示例：

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

不完全是我们想要的！

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