Teach Yourself SQL in 10 Minutes – Page 31 练习

1. Write a SQL statement to retrieve all customer names (cust_name) from the Customers table, and display the results sorted from Z to A.

SELECT cust_name FROM Customers ORDER BY cust_name DESC;

2. Write a SQL statement to retrieve customer ID (cust_id) and order number (order_num) from the Orders table, and sort the results friendly by customer ID and then by order date (order_date) in reverse chronological order.

SELECT cust_id, order_num FROM Orders ORDER BY cust_id, order_date DESC;

3.Our fictions store obviously prefers to sell more expensive items, and lots of them. Write a SQL statement to display the quantity and price (item_price) from the OrderItems table, stored with the highest quantity and highest price first.

SELECT quantity, item_price FROM OrderItems ORDER BY quantity DESC, item_price DESC;

4. What is wrong with the following SQL statement? (Try to figure it out without running it):

SELECT vend_name,  -- ‘,’ is not necessary

FROM Vendors

ORDER BY vend_name DESC;  -- add ‘BY’ here

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