5. Write a query that selects for every customer, the number of orders he has places and the number of items he has bought, including zeros for customers with no orders.
6. Using the query above populate the table Customers_Statistics (Use Insert Statement)

Extra: What is going to happen if you rollback?

Now add a new column to the table called Customer_Status that is a string of maximum length 20; Extra: What is going to happen if you rollback?

7. Now lets update the table so that Customer_Status has the following values:

ok when the number of orders is 0 or 1

good when the number of orders is 2 or more

great when the number of orders is > 5 and the number of items is >5

8. Alter the table so that Number_of_Items cannot be NULL
9. Delete from the table Customers_Statistics all the customers that have not placed any orders
10. Truncate table Customers_Statistics
11. Drop table Customers_Statistics

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8. 

l = CUSTOMER-T CUSTOMER!D CUSTOMERNAME CUSTOMERADDRESS CUSTOMERCITY CUSTOMERSTATE CUSTOMERPOSTALCODE .. CUSTOMERS CUSTOMER-ID CUSTOMER-FIRST-NAME E CUSTOMER-LAST-NAME CUSTOMERADDRESS CUSTOMER CITY - CUSTOMER_STATE CUSTOMERZIP CUSTOMERPHONE CUSTOMER FAX - - B-CUSTOMERS STATISTICS CUSTOMERSHIPADDRESST B- DOESBUSINESSINT EMPLOYEE-T EMPLOYEESKILLST E- LE GENERAL-LEDGER-ACCOUNTS INVOICE LINE ITEMS ITEMS ITEM_D TITLE ARTIST : UNIT-PRICE | E ORDER DETAILS ORDER ID 1 ITEM-ID 0 ORDERI INET ORDERLINEID E ORDERID PRODUCTID ORDEREDQUANTITY ORDERS CUSTOMERID - ORDER_DATE SHIPPED-DATE B- PAYMENT T PAYMENTTYPET PRODUCEDINT B- PRODUCTT B-PRODUCTLINET B- RAWMATERIALT - E- SHIPPED T .. TERMS E TERRITORY-T .. USES_T SUPPLIES-T VENDOR-CONTACTS VENDORT - .. E VENDORS B- WORKCENTERT WORKSIN T