Which distinct name is that?
SELECT DISTINCT t1.product_name FROM products AS t1 JOIN product_characteristics AS t2 ON t1.product_id   =   t2.product_id JOIN CHARACTERISTICS AS t3 ON t2.characteristic_id   =   t3.characteristic_id WHERE t3.characteristic_name   =   "warm"
distinct name refers to DISTINCT(product_name); name that has the characteristic 'warm' refers to joining tables on product_id and characteristic_id where characteristic_name = 'warm';