select lpad('1234',4,'0') from dual select lpad('123',4,'0') from dual select lpad('23',4,'0') from dual select lpad('3',4,'0') from dual select nvl(lpad('',4,'0'),'0000') from dual
select lpad('1234',4,'0') from dual select lpad('123',4,'0') from dual select lpad('23',4,'0') from dual select lpad('3',4,'0') from dual select nvl(lpad('',4,'0'),'0000') from dual