选择查询字符数字ID通过递减订购

Question

我有示例数据

SMMP022011304196
SMMP022011304199    
SMMP022011304197    
SMMP022011304193
SMMP022011304195    
SMMP022011304198    
SMMP022011304192    
SMMP0220113041910   
SMMP022011304191
SMMP022011304194

如果我使用SELECT myfield from mytable order by myfield DESC我造成这样的

SMMP022011304199    
SMMP022011304198    
SMMP022011304197    
SMMP022011304196    
SMMP022011304195    
SMMP022011304194    
SMMP022011304193    
SMMP022011304192    
SMMP0220113041910   
SMMP022011304191

请帮忙做的结果是这样的：

SMMP0220113041910   
SMMP022011304199    
SMMP022011304198    
SMMP022011304197    
SMMP022011304196    
SMMP022011304195    
SMMP022011304194    
SMMP022011304193    
SMMP022011304192    
SMMP022011304191

Answer 1

只是排序字段的长度，然后用长度相等的值：

SELECT myfield from mytable order by 
LENGTH(myfield) DESC,
myfield DESC

SQLFiddle demo

Answer 2

如果数据总是有SMMP在前面，你可以使用如下：

ORDER BY LPAD(REPLACE(myfield,'SMMP',''),15,'0') desc;

该方法的逻辑是忽略在前面的4的炭和仅次于排序数字的数字。

Answer 3

继我先前的评论，排序如下： -

SELECT myfield
FROM mytable
ORDER BY SUBSTRING(myfield, 1, 4) DESC, cast(SUBSTRING(myfield, 5) AS unsigned) DESC

请注意，这仅适用于如果你的领域是固定格式的，随后用NUMERICS 4个字符

Answer 4

这是工作的罚款。下面的代码是SQL Server 2008 R2的工作：

SELECT 
   myfield  
FROM mytable 
ORDER BY 
    LEN(myfield) DESC 
    ,myfield DESC