problem in ORDER BY

[anaspk]

hi i m Anas Raza..
i want to sort a record by a field let supose the field is registration number which is combination of alphabets and intergers,which is like this
b13
b14
b15
b11
b21
b1111
b1121
b123
b131
when i use ORDER BY thn they look like following:
b1111
b1121
b12
b123
b13
b131
b14
b15
b21
but i dont want sorting like this,i want to sort it in human way i mean like this
b11 (Which "ORDER BY" already ignor)
b12
b13
b14
b15
b21
b123
b131
b1111
b1121
plz help me to do that varchar field in order

[SmallPotatoes]

If it will always be the letter "b" followed by digits, then you can do:

SELECT ... ORDER BY CAST(SUBSTR(registration_number, 2) AS UNSIGNED INTEGER)

Advanced tip: If you will be doing frequent queries with large result sets, you should create another column to hold the integer equivalents and optionally put a key on it. Otherwise this will become slow under load.