How to replace number with flexible length

Question

Hi..
Could somebody help me, how to replace any number start with more than 2 digits of "0" become 2 digits "0" only. As example:-
Sample Result
123456789 => 123456789
0123456789 => 0123456789
00123456789 => 00123456789
000123456789 => 00123456789
0000123456789 => 00123456789
00000123456789 => 00123456789
Thank you,
Baharin

Answer 1

Or - to handle the situation when '00' is also in between the word:
SQL> with t as (
select '12300456789' str from dual union
select '0123456789' from dual union 
select '00123456789' from dual union
select '000123456789' from dual union
select '0000123456789' from dual union
select '00000123456789' from dual
select str,
        decode(substr(str,1,2),'00', '00' || ltrim(str,'0'),str) new_str
from   t
STR            NEW_STR        
00000123456789 00123456789    
0000123456789  00123456789    
000123456789   00123456789    
00123456789    00123456789    
0123456789     0123456789     
12300456789    12300456789    
6 rows selected.