Function & Procedure Help

Question

CUST- customer_num, first_name, last_name
DELIVERY - customer_num, free_delivery
INVOICE- customer_num, delivery, item_num
INVENTORY - item_num, price
using just these columns from these tables i have to create a detailed report as to which customers have spent over $700 using a procedure or a function...I then will have to go back into the delivery table and change free_delivery to "YES"
I'm new to sql/pl and i've have tried so many different ways if any one could help me even begin with what directon i should go, I would be thankful
UPDATE DELIVERY SET free_delivery='YES'
WHERE customer_num IN(
SELECT C.customer_num
FROM CUST C
INNER JOIN INVOICE INV ON C.customer_num=INV.customer_num
INNER JOIN INVENTORY INVT ON INV.item_num=INVT.item_num
GROUP BY C.customer_num
HAVING SUM(INVT.price)>700)

Answer 1

I hope you want to convert the above query into a function block that can be called several times. If that is the case, the below block might help.
It will also allow you to pass the amount value by which you can update rows for dynamic amounts.
FUNCTION free_delivery (f_amount NUMBER)
   RETURN BOOLEAN
IS
   rvalue   BOOLEAN;
   v_rows_processed NUMBER;
BEGIN
   UPDATE delivery
      SET free_delivery = 'YES'
    WHERE customer_num IN (SELECT   c.customer_num
                               FROM cust c INNER JOIN invoice inv
                                    ON c.customer_num = inv.customer_num
                                    INNER JOIN inventory invt
                                    ON inv.item_num = invt.item_num
                           GROUP BY c.customer_num
                             HAVING SUM (invt.price) > f_amount);
   v_rows_processed := SQL%ROWCOUNT;
   if (v_rows_processed > 0) then
    rvalue = TRUE;
   else
    rvalue = FALSE;
   end if;                               
   RETURN rvalue;
END;If you want to commit the changes in the function itself it can be done, but not recommended.
Just add commit after the if loop.