Question

我有一个按column排序的查询：

select * from mytable order by column asc — sort table

column类型为varchar，因此输出为：

如果我希望它们按数值排序，我应如何排序，因此输出为：

Answer 1

使用：

order by cast(column as unsigned) asc

Answer 2

如果您希望仅将column视为INT，则可以使用此功能：

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

或者，如果您想将column同时视为INT和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 3

这也应该有效：


order by (0 + column) asc

Answer 4

如果我们只是稍微通过声明修改顺序（在按字段的顺序中添加“+0”），您可以强制MySQL自然地对字段进行排序。

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

Answer 5

    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;

通过转换（替换（actual_user_id，＆＃39; - ＆＃39;，＆＃39;＆＃39;），SIGNED INTEGER）选择*来自varchar_sort顺序

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

用于排序的varchar到数字转换

5 个答案: