What are the names, details and data types of the characteristics which are never used by any product?
create table characteristics (characteristic_name varchar, other_characteristic_details varchar, characteristic_data_type varchar, characteristic_id varchar, PRIMARY KEY (characteristic_name)); create table product_characteristics (characteristic_id varchar, PRIMARY KEY (characteristic_id)); create table characteristics (characteristic_name varchar, other_characteristic_details varchar, characteristic_data_type varchar, PRIMARY KEY (characteristic_name))
select characteristic_name, other_characteristic_details, characteristic_data_type from characteristics except select t1.characteristic_name, t1.other_characteristic_details, t1.characteristic_data_type from characteristics as t1 join product_characteristics as t2 on t1.characteristic_id = t2.characteristic_id