<b>(a)</b> SELECT user_id FROM user_table WHERE user_name='bob'; SELECT cart_item, product_id FROM shopping_cart WHERE user_id=77; SELECT product_name FROM products WHERE product_id=231; SELECT product_name FROM products WHERE product_id=527; SELECT product_name FROM products WHERE product_id=1099; <b>(b)</b> SELECT u.user_id, c.cart_item, p.product_id, p.product_name FROM user_table as u, shopping_cart as c, products as p WHERE u.user_name='bob' AND u.user_id=c.user_id AND c.product_id=p.product_id;
Example 2: Two different ways to get the same data. (a) With a lot of little queries; (b) with a single, more complex query.