ORA-06502 encountered due to negative sign

Question

Problem:
I encountered the error in my sql statement with the message:
declare
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at line 144
I already found the problem:
v_str:= lpad(nvl(to_char((to_number(display_r.CO_AMOUNT)/100),'999,999,999.99'),' '),'15',' ');
DBMS_OUTPUT.PUT_LINE(v_str);Because the value of CO_AMOUNT has negative sign as: 00000000-381250
As such, I would like to seek help in resolving the problem I encountered. Is there a way to still display the output with the negative sign?
Thanks in advance.

Answer 1

The negative sign is not the problem, it's the fact that it's in the middle of the string. SQL expects the sign to be at the beginning (or end) of a number.
This is one of the side effects of using strings to hold numeric data. There are a number of reasons why you might have this behaviour, it really depends on what your app does and how it populates the CO_AMOUNT variable.
Anyway, you can solve this specific problem with a simple LTRIM:
SQL> SELECT to_number('00000000-381250') FROM dual
  2  /
SELECT to_number('00000000-381250') FROM dual
ERROR at line 1:
ORA-01722: invalid number
SQL> SELECT to_number(ltrim('00000000-381250', '0')) FROM dual
  2  /
TO_NUMBER(LTRIM('00000000-381250','0'))
                                -381250
SQL> Cheers, APC