Oracle INVALID_NUMBER exception in my function does not work - oracle

Question

The Oracle function below assign 'A' to number variable.
But the Exception clause does not catch INVALID_NUMBER system exception.
CREATE OR REPLACE FUNCTION TEST2
(P1 IN VARCHAR2)
RETURN NUMBER AS V_VALUE NUMBER;
BEGIN
SELECT(
--SELECT 1/TO_NUMBER(P1)
SELECT 'A'
FROM DUAL
)
INTO V_VALUE
FROM DUAL;
RETURN V_VALUE;
EXCEPTION
WHEN INVALID_NUMBER THEN -- If I change INVALID_NUMBER to OTHERS, then it works.
RETURN -1;
END;
/
SELECT TEST2('1') FROM DUAL;
When I change INVALID_NUMBER to OTHERS, then it works.
How to modify above code to chatch the INVALID_NUMBER exception?

Answer 1

Because you get VALUE_ERROR when ORA-06502 raised as occurs in your case. So, replace INVALID_NUMBER with VALUE_ERROR.
as an example; if the SELECT statement was :
SELECT 5
INTO V_VALUE
FROM DUAL
WHERE TO_NUMBER('A')=1;
you'd get INVALID_NUMBER(ORA-01722) exception.

Answer 2

Some more info (to what Barbaros already told you).
The INVALID_NUMBER Exception (ORA-01722) occurs in a SQL statement when the conversion of a character string into a number fails because the string does not represent a valid number. (In procedural statements, VALUE_ERROR is raised.) This exception is also raised when the LIMIT-clause expression in a bulk FETCH statement does not evaluate to a positive number.
Compare
SQL> select 'a'/2 from dual;
select 'a'/2 from dual
*
ERROR at line 1:
ORA-01722: invalid number
to
SQL> declare
2 l_num number;
3 begin
4 l_num := 'a' / 2;
5 end;
6 /
declare
*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at line 4
to
SQL> declare
2 l_num number;
3 begin
4 select 'a' / 2 into l_num from dual;
5 end;
6 /
declare
*
ERROR at line 1:
ORA-01722: invalid number
ORA-06512: at line 4
Isn't that nice of Oracle? More or less the same thing, but different response.