Varchar to number conversion for sorting

Question

I have a query ordered by column:

select * from mytable order by column asc — sort table

column type is varchar, so the output is:

1
10
100
11
12
13

How should I sort if I want them to sort by numeric value so the output is:

1
10
11
12
13
100

Answer 1

You can use this if you want to treat column as INT only:

SELECT * FROM mytable ORDER BY column+0;
1
10
11
12
13
100

Or this if you want to treat column as both INT and VARCHAR

SELECT * FROM mytable ORDER BY column+0, column; #this will sort the column by VARCHAR first and then sort it by INT

abc
xyz
1
10
11
12
13
100

Answer 2

If we simply modify the order by declaration slightly (add “+0″ to the order by field), you can force MySQL to sort the field naturally.

 > select * from mytable order by column+0 asc;
 column
 1 
 10
 11
 12
 13 
 100

Answer 3

This should work as well:

order by (0 + column) asc

Answer 4

    Added a full code script here , but need to sort 1001 and 1002 before - as well.
We have total 5 solution , means 5 different queries as solution with full script.


=============================================================
    SET NAMES utf8;
    SET foreign_key_checks = 0;
    SET time_zone = 'SYSTEM';
    SET sql_mode = 'NO_AUTO_VALUE_ON_ZERO';

    DROP TABLE IF EXISTS `varchar_sort`;
    CREATE TABLE `varchar_sort` (
      `user_id` int(11) NOT NULL AUTO_INCREMENT,
      `actual_user_id` varchar(200) DEFAULT NULL,
      PRIMARY KEY (`user_id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=latin1;

    INSERT INTO `varchar_sort` (`user_id`, `actual_user_id`) VALUES
    (1, '1001-4'),
    (2, '1001-1'),
    (3, '1001-111'),
    (4, '1002-1'),
    (5, '1001-66'),
    (6, '1001-100'),
    (7, '1001-110');


    SELECT user_id,actual_user_id,CONVERT(SUBSTRING_INDEX(actual_user_id,'-',-1),UNSIGNED INTEGER) AS num
    FROM varchar_sort
    ORDER BY num;


    SELECT user_id,actual_user_id
    FROM varchar_sort
    ORDER BY CONVERT(SUBSTRING(actual_user_id, 6), SIGNED INTEGER);


    SELECT user_id,actual_user_id
    FROM varchar_sort
    ORDER BY CONVERT(SUBSTRING(actual_user_id, LOCATE('-', actual_user_id) + 1), SIGNED INTEGER);


    SELECT *, CAST(SUBSTRING_INDEX(actual_user_id, '-', -1) AS UNSIGNED) as num FROM varchar_sort ORDER BY num;

select * from varchar_sort order by convert( replace(actual_user_id, '-',''), SIGNED INTEGER ) asc

    **Need to sort 1001 and 1002 as well.**

Answer 5

Use:

order by cast(column as unsigned) asc