php mysql 按多列选择顺序

Question

我有一个问题。我想排列列的顺序减少。 iPhone4、iPhone5、iPhone6。例如:

Name |iphone4 |iphone5|iphone6 
john | 6      | 7     | 8      
Smith| 6      | 9     | 8      
Louis| 6      | 7     | 10      
Nick | 7      | 7     | 8      
john | 2      | 7     | 4 
Smith| 7      | 7     | 5

这是我的mysql

Select Name, SUM(iphone4) ,SUM(iphone5),SUM(iphone6) from orders group by Name order by iphone4  DESC, iphone5 DESC, iphone6  DESC

但它仅适用于 iphone4 和 iphone5 列。其余的，iphone6不行谁能帮助我？

Answer 1

如 Cast Functions and Operators: 中所述

The type for the result can be one of the following values:

• BINARY[(N)]
• CHAR[(N)]
• DATE
• DATETIME
• DECIMAL[(M[,D])]
• SIGNED [INTEGER]
• TIME
• UNSIGNED [INTEGER]

所以你的查询将是这样的

Select m.*
from mark m
order by CAST(mathematics AS UNSIGNED) DESC, CAST(physics AS UNSIGNED) DESC, CAST(chemistry AS UNSIGNED) DESC;