Handling NULL in Oracle Function

Question

I try to handle NULL with IS NULL in side the Function. But I some how can't do it. Control always goes to NO_DATA_FOUND Exception block.
In BEGIN block, if I try to handle with IS NULL condition but it doesn't work. But if I use DBMS_OUTPUT.PUTLINE and display the variable with NVL, it tells me it is NULL.
My code is like;
<code>
FUNCTION F_GetProductKey (p_CompanyCod varchar2, p_ProductCod varchar2) return number;
as
vi_ProductKey Number;
BEGIN
DBMS_OUTPUT.PUT_LINE( NVL(p_ProductCod,'abc') <----- This displays 'abc'
IF p_ProductCod IS NULL THEN
SELECT PRODUCT_KEY in vi_ProductKey from DIM_PRODUCT WHERE Product_Cod=-2;
ELSE <---- Control Always Goes to ELSE even p_ProductCod is NULL & then it goes to NO_DATA_FOUND Exception
SELECT PRODUCT_KEY in vi_ProductKey from DIM_PRODUCT WHERE Product_Cod=p_ProductCod AND COMPANY_COD = p_CompanyCod ;
END IF;
return vi_Product_Key;
EXCEPTION
     WHEN NO_DATA_FOUND THEN
     return -20060;
WHEN OTHERS THEN
return -20001;
END;
</code>
I've a hard coded value in table for Product_Cod=-2, so I should never get No_Data_Found exception if ProductCod is NULL. I checked, for CompanyCod and it is NOT NULL when I call function.
I Googled to look at what I'm doing wrong. I find that NULL values can be handled by ISNULL but some how it doesn't work in my case.
Is there any other way to handle NULL inside function??

Answer 1

I've a hard coded value in table for Product_Cod=-2, so I should
never get No_Data_Found exception if ProductCod is NULL.Are you sure? It seems to me the behaviour you describe could equally well be explained by the control going down the IF ... IS NULL branch and then not finding the PRODUCT_COD in question.
Cheers, APC
Blog : http://radiofreetooting.blogspot.com/
P.S. Having read your subsequent message, specifically this
Product_cod is varchar2. It is actually comparing to
'UNK' not -2 in side the code.I am even more certain that the problem lies in your data. Larry Ellison did not become a multi-billionnaire on the basis of code which behaved in an unpredictable fashion.
Message was edited by:
APC