<pre class="c" name="code">CREATE TABLE ithelp150302(
id TINYINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
type CHAR(16) NOT NULL
);

INSERT INTO ithelp150302(type) VALUES
("mobile_banner9"),("mobile_banner8"),("mobile_banner7"),
("mobile_banner4"),("mobile_banner5"),("mobile_banner6"),
("mobile_banner3"),("mobile_banner2"),("mobile_banner1"),
("mobile_banner10");

SELECT *
  FROM ithelp150302
 ORDER BY CAST(SUBSTRING(type FROM 14) AS UNSIGNED) DESC;

+----+-----------------+
| id | type            |
+----+-----------------+
| 10 | mobile_banner10 |
|  1 | mobile_banner9  |
|  2 | mobile_banner8  |
|  3 | mobile_banner7  |
|  6 | mobile_banner6  |
|  5 | mobile_banner5  |
|  4 | mobile_banner4  |
|  7 | mobile_banner3  |
|  8 | mobile_banner2  |
|  9 | mobile_banner1  |
+----+-----------------+

基本上，type欄位中，mobile_banner10，比對到『1』的時候，它比9小，所以
反向排序，自然會被排到9的後面
或許，你可以試試這麼寫：

<pre class="c" name="code">
select * from dh_button where type like '%mobile_banner%' order by CHAR_LENGTH(type) desc,type desc

先依據欄位內容長度排序，再依欄位排序
手邊沒有MySql，所以沒測試過，請自行測試～～

考慮直接讓他變成兩位數，如何?

mobile_banner01
mobile_banner02
.....
...
..

<pre class="c" name="code">select * from dh_button where type like '%mobile_banner%' order by CONVERT(REPLACE (type, 'mobile_banner', ''),UNSIGNED INTEGER) desc