Display error message instead of 'no rows selected' - sql

Question

I want my function to display 'Empty Invoice Found!' Or 'Invoice Not Found' error messages.
But when I select the data with error(doesnt exist in the table), it return 'no rows selected'. Please guide me with the correct way to SELECT.
SET ECHO ON;
SET SERVEROUTPUT ON;
CREATE OR REPLACE FUNCTION totalInvoiceAmount(InvoiceNo IN INVOICE_ITEM.InvoiceNumber%TYPE)
RETURN NUMBER IS
TotalCost NUMBER(20);
CURSOR X_RECORD IS SELECT * FROM INVOICE_ITEM;
CURSOR Y_RECORD IS SELECT * FROM INVOICE_ITEM;
tempCost NUMBER:=0;
InvoiceCheck BOOLEAN:=FALSE;
InvoiceEmpty BOOLEAN:=TRUE;
BEGIN
FOR Record IN X_RECORD LOOP
IF Record.InvoiceNumber = InvoiceNo THEN
InvoiceCheck:=TRUE;
EXIT;
ELSE
InvoiceCheck:=FALSE;
END IF;
END LOOP;
FOR Record IN Y_RECORD LOOP
IF Record.InvoiceNumber = InvoiceNo AND InvoiceCheck=FALSE THEN
InvoiceEmpty:=TRUE;
EXIT;
ELSE
InvoiceEmpty:=FALSE;
END IF;
END LOOP;
IF InvoiceCheck=FALSE AND InvoiceEmpty=FALSE THEN
DBMS_OUTPUT.PUT_LINE('Invoice Not Found!');
RETURN -1;
ELSIF InvoiceCheck=FALSE AND InvoiceEmpty=TRUE THEN
DBMS_OUTPUT.PUT_LINE('Empty Invoice Found!');
RETURN 0;
ELSE
FOR Record IN X_RECORD LOOP
IF Record.InvoiceNumber = InvoiceNo THEN
tempCost:=tempCost+(Record.UnitPrice*Record.Quantity);
END IF;
END LOOP;
TotalCost:=tempCost;
RETURN TotalCost;
END IF;
END;
/
SELECT invoicenumber,totalInvoiceAmount(invoicenumber) AS "Total Cost" FROM INVOICE_ITEM Where invoicenumber=2011011;
SELECT invoicenumber,totalInvoiceAmount(invoicenumber) AS "Total Cost" FROM INVOICE_ITEM where invoicenumber=2011010;

Answer 1

The messages you want come from a function which you are calling in a SELECT statement. So if that SELECT returns no rows there are are no rows which can be used to call that function.
I'm afraid it's not clear what you're trying to achieve, but whatever it is you need a different approach. Having said which I suggest something like this might be give you what you want (in a more orthodox and more efficient fashion):
SELECT invoicenumber,
sum(UnitPrice*Quantity) AS "Total Cost"
FROM INVOICE_ITEM
where invoicenumber=2011010
group by InvoiceNumber;

Answer 2

SET ECHO ON;
SET SERVEROUTPUT ON;
CREATE OR REPLACE FUNCTION totalInvoiceAmount(InvoiceNo IN INVOICE_ITEM.InvoiceNumber%TYPE)
RETURN NUMBER IS
TotalCost NUMBER(20);
invoice_not_found EXCEPTION ;
empty_invoice_found EXCEPTION ;
CURSOR X_RECORD IS SELECT * FROM INVOICE_ITEM;
CURSOR Y_RECORD IS SELECT * FROM INVOICE_ITEM;
tempCost NUMBER:=0;
InvoiceCheck BOOLEAN:=FALSE;
InvoiceEmpty BOOLEAN:=TRUE;
BEGIN
FOR Record IN X_RECORD LOOP
IF Record.InvoiceNumber = InvoiceNo THEN
InvoiceCheck:=TRUE;
EXIT;
ELSE
InvoiceCheck:=FALSE;
END IF;
END LOOP;
FOR Record IN Y_RECORD LOOP
IF Record.InvoiceNumber = InvoiceNo AND InvoiceCheck=FALSE THEN
InvoiceEmpty:=TRUE;
EXIT;
ELSE
InvoiceEmpty:=FALSE;
END IF;
END LOOP;
IF InvoiceCheck=FALSE AND InvoiceEmpty=FALSE THEN
--DBMS_OUTPUT.PUT_LINE('Invoice Not Found!');
RAISE invoice_not_found;
--RETURN -1;
ELSIF InvoiceCheck=FALSE AND InvoiceEmpty=TRUE THEN
--DBMS_OUTPUT.PUT_LINE('Empty Invoice Found!');
RAISE empty_invoice_found
RETURN 0;
ELSE
FOR Record IN X_RECORD LOOP
IF Record.InvoiceNumber = InvoiceNo THEN
tempCost:=tempCost+(Record.UnitPrice*Record.Quantity);
END IF;
END LOOP;
TotalCost:=tempCost;
RETURN TotalCost;
END IF;
EXCEPTION
when invoice_not_found then
DBMS_OUTPUT.PUT_LINE('Invoice Not Found!');
raise -1;
when empty_invoice_found then
DBMS_OUTPUT.PUT_LINE('Empty Invoice Found!');
raise 0;
END;
You can catch it in an exception and handle it accordingly , let me know if it works