This should sort alphanumeric field like:
1/ Number only, order by 1,2,3,4,5,6,7,8,9,10,11
etc...
2/ Then field with text like: 1foo, 2bar, aaa11aa, aaa22aa, b5452
etc...
SELECT MyField
FROM MyTable
order by
IF( MyField REGEXP '^-?[0-9]+$' = 0,
9999999999 ,
CAST(MyField AS DECIMAL)
), MyField
The query check if the data is a number, if not put it to 9999999999 , then order first on this column, then order on data with text
Good luck!