hibernate - HQL : Order by varchar2 as INT -

i'm working on statement in hql , have results sorted numbers.

kind of results can have : dr71 frein resf-37 r-37 ...

i have sorted numbers composed of.

i had :

select distinct r.type  reference r order replace(replace(replace(r.type, '-', ''), 'f', ''), ' ', '') 

it enough because @ beginning, r, - , f used. have solution supporting every characters.

i tried :

order cast(r.type int) 

but gives sql error: 1722, sqlstate: 42000

any idea how ?