Find the id of suppliers whose average amount purchased for each product is above 50000 or below 30000
SELECT supplier_id FROM Product_Suppliers GROUP BY supplier_id HAVING avg ( total_amount_purchased )  > 50000 OR avg ( total_amount_purchased )  < 30000
average amount purchased for each product refers to AVG(total_amount_purchased); above 50000 or below 30000 refers to conditions > 50000 OR < 30000;