What are id and name of the products whose price is lower than 600?
select product_id, product_name from products where product_price < 600
What are id and name of the products whose price is higher than 900?
select product_id, product_name from products where product_price > 900
How many products have price lower than 600 or higher than 900?
select count ( * ) from products where product_price < 600 or product_price > 900