select nvl2(translate(a.data, ‘\1234567890.‘, ‘\‘), null, a.data) n, a.data  from rpt_detail a;

1 create   or   replace   function   isNumber(p_in   varchar2)   return   boolean   as  2         i   number;  3 begin  4         i:=to_number(p_in);  5         return   true;  6 exception        7         when   others   then    8               return   false;  9 end   ;