SQL order string as number

Question

I have numbers saved as VARCHAR to a MySQL database. I can not make them INT due to some other depending circumstances.

It is taking them as character not as number while sorting.

In database I have

1 2 3 4 5 6 7 8 9 10...

On my page it shows ordered list like this:

1 10 2 3 4 5 6 7 8 9

How can I make it appear ordered by numbers ascending?

Answer 1

If possible you should change the data type of the column to a number if you only store numbers anyway.

If you can't do that then cast your column value to an integer explicitly with

select col from yourtable
order by cast(col as unsigned)

or implicitly for instance with a mathematical operation which forces a conversion to number

select col from yourtable
order by col + 0

BTW MySQL converts strings from left to right. Examples:

string value  |  integer value after conversion
--------------+--------------------------------
'1'           |  1
'ABC'         |  0   /* the string does not contain a number, so the result is 0 */
'123miles'    |  123 
'$123'        |  0   /* the left side of the string does not start with a number */

Answer 2

Another way, without using a single cast.

(For people who use JPA 2.0, where no casting is allowed)

select col from yourtable
order by length(col),col

EDIT: only works for positive integers