Would you please show me the ids of all employees who don't destroy any documents?
select employee_id from employees except select destroyed_by_employee_id from documents_to_be_destroyed
What are their names?
select employee_name from employees except select destroyed_by_employee_id from documents_to_be_destroyed
Would you please show me the ids of all employees who do destroy any documents?
select employee_id from employees as t1 join documents_to_be_destroyed as t2 on t1.employee_id = t2.destroyed_by_employee_id