CREATE TABLE products (product_id VARCHAR)
CREATE TABLE CHARACTERISTICS (characteristic_name VARCHAR, characteristic_id VARCHAR)
CREATE TABLE product_characteristics (product_id VARCHAR, characteristic_id VARCHAR)

What is the characteristic name used by most number of the products?
SELECT t3.characteristic_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 GROUP BY t3.characteristic_name ORDER BY COUNT(*) DESC LIMIT 1
SELECT "t3"."characteristic_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" GROUP BY "t3"."characteristic_name" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1