Function does not return what I am expecting

In my function below开发者_开发知识库 I am trying to understand why it only returns BLAH if I pass in 01356666 and then a null value for anything else passed in. My expectation was that it would return BLAH regardless of what was passed in since I reset the str_mgrin_out after I do the SELECT INTO. I have been testing this in Oracle 10g.

CREATE OR REPLACE FUNCTION GET_MANAGERGIN2 (str_empgin_in IN varchar2)
RETURN varchar2
AS
str_mgrgin_out varchar2(10);
BEGIN
  SELECT 'FOO' INTO str_mgrgin_out FROM dual WHERE str_empgin_in = '01356666';

  str_mgrgin_out := 'BLAH';

  RETURN str_mgrgin_out;
END GET_MANAGERGIN2;
/

-- Returns null but expecting BLAH
SELECT GET_MANAGERGIN2('00356666') FROM dual;
-- Returns BLAH
SELECT GET_MANAGERGIN2('01356666') FROM dual;

I'd assume that this is because if the SELECT INTO doesn't return exactly one value into str_mgrgin_out it'll throw an exception, so the str_mgrgin_out := 'BLAH'; line never gets executed.

I think the error would be ORA-01403.

Try adding an exception handler at the end as:

Exception
    When Others Then
         str_mgrgin_out := 'BLAH';

You might have to surround it with a BEGIN...END as well so it would be:

CREATE OR REPLACE FUNCTION GET_MANAGERGIN2 (str_empgin_in IN varchar2)
RETURN varchar2
AS
str_mgrgin_out varchar2(10);
BEGIN
    BEGIN
        SELECT 'FOO' INTO str_mgrgin_out FROM dual WHERE str_empgin_in = '01356666';

        str_mgrgin_out := 'BLAH';
        Exception
            When Others THen
                str_mgrgin_out := 'BLAH';
   END;
   RETURN str_mgrgin_out;
END GET_MANAGERGIN2;

The select matches zero rows, with raises a NO_DATA_FOUND PL/SQL exception.

However NO_DATA_FOUND isn't recognized as an SQL error, merely the end of the result set.

Therefore when used in a SELECT, a null value is returned.