Question: What are characteristic names used at least twice across all products?
Schema: create table products (product_id varchar, PRIMARY KEY (product_id)); create table characteristics (characteristic_name varchar, characteristic_id varchar, PRIMARY KEY (characteristic_name)); create table product_characteristics (product_id varchar, characteristic_id varchar, PRIMARY KEY (product_id))
SQL: 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 having count(*) >= 2