What are the average amount purchased and value purchased for the supplier who supplies the most products
SELECT avg ( total_amount_purchased )  ,  avg ( total_value_purchased )  FROM Product_Suppliers WHERE supplier_id   =    ( SELECT supplier_id FROM Product_Suppliers GROUP BY supplier_id ORDER BY count ( * )  DESC LIMIT 1 ) 
average amount purchased = AVG(total_amount_purchased); average value purchased = AVG(total_value_purchased); supplier who supplies the most products refers to supplier with MAX(COUNT(product_id));