Consider the relations: Customer(CID, Name, City, State), Order(OID, CID, Date), and Product(PID, ProductName, Price) LineItem(LID, OID,PID, Number, TotalPrice), where CID is a customer id and is a key for Customer, OID is an order id and is a key for Order, and LID is a line item id and is a key for LineItem. In addition the attribute CID of Order is a foreign key referring to the CID of Customer, that is, for each CID c of Order there is exactly one tuple of Customer whose CID attribute is c. The OID of LineItem is a foreign key referring to the OID of Order. There are several line items for the same order, a line item refers to a product and contains the quantity ordered for the product.

Express the following queries Algebra:

1. List the customers who ordered computers

2. List the other products bought by customers who bought computers

3. List the customers who did not place any order since January 1 2014

4. List the products bought by at least one customer of Newark

5. List the products bought by all the customers of Newark

6. List the products ordered only by the customers of Newark

7. List the products never ordered by customers of New Jersey