Show the ids of all employees who have destroyed a document.
SELECT DISTINCT Destroyed_by_Employee_ID FROM Documents_to_be_destroyed
SELECT DISTINCT Destroyed_by_Employee_ID FROM Documents_to_be_destroyed
[{'Destroyed_by_Employee_ID': 138}, {'Destroyed_by_Employee_ID': 173}, {'Destroyed_by_Employee_ID': 156}, {'Destroyed_by_Employee_ID': 136}, {'Destroyed_by_Employee_ID': 99}, {'Destroyed_by_Employee_ID': 38}, {'Destroyed_by_Employee_ID': 55}]