Mysql order by 类型转换

 

起因：写sql order by一个字段，字段类型是varchar里面存储的是数字，要按数字大小排序，而不是按首字符出现先后顺序，这就需要转换

RDER
 BY
 CAST(
`pic_number`
 AS
 SIGNED)

and for reverse order

ORDER
 BY
 CAST(
`pic_number`
 AS
 SIGNED)
 DESC

And it worked like a charm!

Function is as simple to use as:

CAST(
expr AS
 type)

Other possible conversion types you may need are:

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