PHP Code:
10:20:08 SQL> select * from my_table ;

CODE_ID
------------------------------
G0DE-0-10047514
M0DF-1-10000281
T0DH-3-20500819
R0DJ-2-10603746
G0DY-0-20006783
G0DZ-0-20049734
G0E0-0-10004325
G0E1-0-10049593
A20T-0-EMS00038
D20T-0-EMS00039
S20T-0-EMS00041
M20T-0-EMS00234

12 rows selected.

SQL>  select code_id,
        (case
         when ascii(substr(code_id,8,1))>= 48 and 
              ascii(substr(code_id,8,1)) <= 57  then
             (substr(code_id,8,2)||'-'||to_char(to_number(substr(code_id,-6))))
         else substr(code_id,-8)
          end) newstr
   from my_table;

CODE_ID                        NEWSTR
------------------------------ -------------------------------------------
G0DE-0-10047514                10-47514
M0DF-1-10000281                10-281
T0DH-3-20500819                20-500819
R0DJ-2-10603746                10-603746
G0DY-0-20006783                20-6783
G0DZ-0-20049734                20-49734
G0E0-0-10004325                10-4325
G0E1-0-10049593                10-49593
A20T-0-EMS00038                EMS00038
D20T-0-EMS00039                EMS00039
S20T-0-EMS00041                EMS00041
M20T-0-EMS00234                EMS00234

12 rows selected.

10:20:35 SQL> 
Tamil