Question

I’m using PHP and MySQL.

I have $pallet and it has values like this:

P01  
P02  
P12  
P20  
P05

How can I sort these values as:

P01  
P02  
P05  
P12  
P20  

Answer 1

If the values always start with ‘P’ then you could strip out the ‘P’, convert the rest into a number and then ORDER BY that number ASC. Hence:

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

EDIT

Here is an example of how sorting alphabetically works:

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;

Result:

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

Not quite what we wanted!

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

Result:

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