Answer 4
This is just Problem 1 in disguise:
the GROUP BY just performs a back-handed DISTINCT operation!
SELECT O.Order_ID,
O.Order_Date, C.Name, L.Line_ID, L.Quantity, I.Name
FROM Orders O, Order_Types T, Order_Lines L,
Items I, Customers C
WHERE
O.Customer_ID = :B1
AND L.Order_ID =
O.Order_ID
AND I.Item_ID =
L.Item_ID
AND
C.Customer_ID = O.Customer_ID
GROUP BY O.Order_ID, O.Order_Date,
C.Name, L.Line_ID, L.Quantity, I.Name;