Question: Show the ids of all employees who don't destroy any document.
Schema: create table employees (employee_id varchar, destroyed_by_employee_id varchar, PRIMARY KEY (employee_id)); create table documents_to_be_destroyed (employee_id varchar, destroyed_by_employee_id varchar, PRIMARY KEY (employee_id))
SQL: select employee_id from employees except select destroyed_by_employee_id from documents_to_be_destroyed