1. List the department IDs for departments that do not contain the job ID ST_CLERK, using SET
   operators.

2. Display the country ID and the name of the countries that have no departments located in
   them, using SET operators.

3. Produce a list of jobs for departments 10, 50, and 20, in that order. Display job ID and
   department ID, using SET operators.

4. List the employee IDs and job IDs of those employees who currently have the job title that they
   held before beginning their tenure with the company.

5. Write a compound query that lists the following:
   • Last names and department ID of all the employees from the EMPLOYEES table,
   regardless of whether or not they belong to any department
   • Department ID and department name of all the departments from the DEPARTMENTS
   table, regardless of whether or not they have employees working in them