How many characteristics does the product named "sesame" have?
SELECT count ( * )  FROM products AS t1 JOIN product_characteristics AS t2 ON t1.product_id   =   t2.product_id WHERE t1.product_name   =   "sesame"
number of characteristics refers to COUNT(*); product named 'sesame' refers to WHERE product_name = 'sesame'; joining tables to count characteristics of a specific product;