Table schema:
CREATE TABLE CHARACTERISTICS (characteristic_id VARCHAR); CREATE TABLE products (product_id VARCHAR, product_name VARCHAR); CREATE TABLE product_characteristics (product_id VARCHAR, characteristic_id VARCHAR)

Question: Find the number of characteristics that the product "flax" has.
SQL: SELECT COUNT(*) 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 t1.product_name = "flax"