CREATE TABLE Documents_to_be_destroyed (employee_id VARCHAR(255), Destruction_Authorised_by_Employee_ID VARCHAR(255)); CREATE TABLE Employees (employee_id VARCHAR(255), Destruction_Authorised_by_Employee_ID VARCHAR(255))
Show the ids of the employees who don't authorize destruction for any document.
    
SQL: SELECT employee_id FROM Employees EXCEPT SELECT Destruction_Authorised_by_Employee_ID FROM Documents_to_be_destroyed