Function returned without value - sql

Question

This is the function which I designed. It got complied successfully
CREATE OR REPLACE FUNCTION "F_CHECK"
(
p_id IN VARCHAR2
p_name IN VARCHAR2)RETURN VARCHAR2
is
v_id VARCHAR2;
v_name VARCHAR2;
cnt pls_integer;
BEGIN
IF id IS NULL THEN
RETURN NULL;
END IF;
SELECT COUNT(*) INTO cnt from emp_new where id = p_id;
IF (cnt > 0) THEN
SELECT id, name INTO v_id, v_name from emp_new where id=p_id;
IF (v_id is null and p_id is null and v_name is null and p_name is null) THEN
return NULL;
ELSE
IF (v_name =trunc(p_name)) then
return NULL;
else
insert into employees values(p_id,p_name,sysdate);
end if;
end if;
end if;
exception
when DUP_VAL_ON_INDEX THEN
raise application error (-20001, 'NAME EXISTS UNDER DIFFERENT ID');
END F_CHECK;
But I'm not getting the expected result, when I execute the function
select F_CHECK(1,1) from dual;
ERROR I'M getting is:
SQL EEROR: ORA-06503: PL/SQL : FUNCTION RETURNED WITHOUT VALUE

Answer 1

You must return a value when the execution flow reaches (around line 22)
...
else
insert into employees values(p_id,p_name,sysdate);
end if;
...
In this case, the function does not return a value which is expected by the caller, hence the error.
You can instruct the PL/SQL compiler to warn you about such code (and other problems) with
ALTER SESSION SET PLSQL_WARNINGS='ENABLE:ALL'; prior to compilation.

Answer 2

One of the possible causes of exceptions that you will get when you run this code is: If your select into didn't return a value, you will get an exception, an nu-handled exception
Even though you have a return NULL in the end of the function, but still you need to catch all the exceptions that might occur
The area where you need to take care of is:
SELECT id, name INTO v_id, v_name from emp_new where id=p_id;
Surround it by Begin ... EXCEPTION WHEN NO_DATA_FOUND THEN ... END; block
Also, your insert statement might cause an exception if you violated some constraints on your table, so you might need to handle that also
Have a look at Error Handling in Oracle
Below is your updated code, also fixed code regarding the extra parenthesis
Edited
CREATE OR REPLACE FUNCTION F_CHECK
(
P_ID EMP_NEW.ID%TYPE,
P_NAME EMP_NEW.NAME%TYPE
)
RETURN VARCHAR2 IS
V_ID EMP_NEW.ID%TYPE;
V_NAME EMP_NEW.NAME%TYPE;
CNT NUMBER;
BEGIN
--IF ID IS NULL THEN
-- What is ID ?? is it P_ID
--Changed below
IF P_ID IS NULL THEN
RETURN 'Error: Add Value For Id';
END IF;
IF P_NAME IS NULL THEN
RETURN 'Error: Add Value For Name';
END IF;
SELECT
COUNT(*) INTO CNT FROM EMPLOYEES
WHERE ID = P_ID;
IF (CNT > 0) THEN
SELECT
ID, NAME INTO V_ID, V_NAME
FROM
EMP_NEW
WHERE
ID=P_ID;
----------------------------------------------------------------------------------------
--IF V_ID IS NULL AND P_ID IS NULL AND V_NAME IS NULL AND P_NAME IS NULL THEN
--The code above will always evaluate to False because P_ID at this stage is not null!
--Also, if P_Name must have a value, check it at the begining along with the ID, not here
----------------------------------------------------------------------------------------
IF V_ID IS NULL AND V_NAME IS NULL THEN
RETURN 'Error: Not found details';
ELSE
--Details are found
IF (V_NAME = TRUNC(P_NAME)) THEN
RETURN 'Name already assigned to this id';
ELSE --Its a new name, add it
INSERT INTO EMPLOYEES VALUES(P_ID,P_NAME,SYSDATE);
--Make sure your columns are only three and in the correct order as the Values specified
END IF;
END IF;
END IF;
RETURN 'Ok, added';
EXCEPTION
WHEN DUP_VAL_ON_INDEX THEN
raise application error (-20001, 'NAME EXISTS UNDER DIFFERENT ID');
END F_CHECK;

Answer 3

A function MUST ALWAYS RETURN a VALUE of proper data type. Else, it would throw the following error:
ORA-06503: PL/SQL: Function returned without value
Cause: A call to PL/SQL function completed, but no RETURN statement was executed.
Action: Rewrite PL/SQL function, making sure that it always returns a value of a proper type.
Read ORA-06503: PL/SQL: Function returned without value
DB version : 11.2.0.2.0
Let’s see the various scenarios of this error :
Without a RETURN statement in the function body and without exception handler(most stupid way):
SQL> set serveroutput on
SQL> CREATE OR REPLACE FUNCTION f_test(i_val NUMBER)
2 RETURN NUMBER AS
3 o_val NUMBER;
4 BEGIN
5 SELECT 100 / i_val
6 INTO o_val
7 FROM DUAL;
8 END;
9 /
Function created
SQL> select f_test(100) from dual;
select f_test(100) from dual
ORA-06503: PL/SQL: Function returned without value
ORA-06512: at "F_TEST", line 8
Now, in the above code, the mathematical logic was correct, hence there was no SQL error to override the PL/SQL error. Let’s see how ORA-01476 will override the ORA-06503 error.
SQL> CREATE OR REPLACE FUNCTION f_test(i_val NUMBER)
2 RETURN NUMBER AS
3 o_val NUMBER;
4 BEGIN
5 SELECT 100 / i_val
6 INTO o_val
7 FROM DUAL;
8 END;
9 /
Function created
SQL> select f_test(0) from dual;
select f_test(0) from dual
ORA-01476: divisor is equal to zero
ORA-06512: at "F_TEST", line 5
Well, that’s quite obvious, isn’t it?
Without a RETURN statement in the exception handler(most common mistake):
SQL> CREATE OR REPLACE FUNCTION f_test(i_val NUMBER)
2 RETURN NUMBER AS
3 o_val NUMBER;
4 BEGIN
5 SELECT 100 / i_val
6 INTO o_val
7 FROM DUAL;
8
9 RETURN o_val;
10
11 EXCEPTION
12 WHEN OTHERS THEN
13 NULL;
14 END;
15 /
Function created
SQL> select f_test(0) from dual;
select f_test(0) from dual
ORA-06503: PL/SQL: Function returned without value
ORA-06512: at "F_TEST", line 14
Now let’s put a RETURN statement at required places and the code should work fine without any error:
SQL> CREATE OR REPLACE FUNCTION f_test(i_val NUMBER)
2 RETURN NUMBER AS
3 o_val NUMBER;
4 BEGIN
5 SELECT 100 / i_val
6 INTO o_val
7 FROM DUAL;
8
9 RETURN o_val;
10
11 EXCEPTION
12 WHEN OTHERS THEN
13 DBMS_OUTPUT.PUT_LINE('Came inside Exception handler');
14 RETURN 0;
15 END;
16 /
Function created
SQL> select f_test(0) from dual;
F_TEST(0)
0
Came inside Exception handler
Bottom line is that :
A function MUST ALWAYS RETURN a value of proper datatype, no matter from the body or exception.
We must do something with the error not just return junk. We must RAISE/log error and handle it, do something about the error so that underlying process has no impact.
Lastly, not to forget, EXCEPTION WHEN OTHERS THEN NULL; –> is itself a bug in the code waiting for its chance to break the code.