SQL & PL/SQL :: Multiply Rows From Different Tables?

I have the task that I have to determine the number of parts that need to be produced based on the number of products sold for the day (each product consists of many parts).

I am using SQL 11g Express.

The report would look something like this:

{OrderDate PartID PartDesc NumOfParts(Total for that day)
10-24-2011 2001 12" X 12" Solid Shelf 108
10-24-2011 2003 12" X 24" Solid Shelf 32
10-24-2011 3001 96" Side Panel 50

[code].......

My issue is, I can't get the equation right to produce the total number of parts. I think I need to multiply ProductPart.NumOfParts by SUM(CustOrder.Qty) Group by CustOrder.SKU.

Below I have what the calculations should look like

SKU PartID Total Parts Needed by SKU
DVCK1212 1001 42 (7 orders * 6 shelves)
DVCK1812 1002 0 (NONE)
DVCK2412 1003 42 (7 orders * 6 shelves)
DVCK3012 1004 78 (13 orders * 6 shelves)

[code].......

Here's my script:

/**PRODUCT**/
CREATE table Product
(
SKU VARCHAR2(10) NOT NULL,
ProdDesc VARCHAR2(50) NOT NULL,
Price NUMBER(5,2),
PRIMARY KEY(SKU)
);

[code].......

Query 1

SELECT ProductPart.NumOfParts
FROM ProductPart,
( SELECT CustOrder.SKU,
sum(CustOrder.qty) cust_qty_sum
FROM CustOrder

[code].......

Result: I am only getting a total of 2 parts

Query 2

SELECT ProductPart.Qty,
ProductPart.PartID,
ProductPart.PartDesc
(SELECT COUNT(CustOrder.SKU)
FROM CustOrder
GROUP BY CustomerOrder.SKU)TotalProducts,

[code].......

ORA-00936: missing expression

Query 3

SELECT Part.PartDesc.
ProductPart.NumOfParts
FROM ProductPart, Part
( SELECT CustOrder.SKU,
sum(CustOrder.qty) cust_qty_sum
FROM CustOrder

[code].......

ORA-00933: SQL command not properly ended

Query 4

SELECT o.OrderDate AS "Date Ordered",
o.OrderDate + 5 AS "Date Due",
pp.PartID AS "Part No.",
pp.NumOfParts * COUNT(o.SKU) AS "Qty"
FROM CustOrder o

[code].......

ORA-00934: group function is not allowed here