What is the lowest salary across all departments?
select min(salary) from employees group by department_id
What information is available for employees who make that much?
select * from employees where salary in (select min(salary) from employees group by department_id)
What are their first and last names and department ids?
select first_name, last_name, department_id from employees where salary in (select min(salary) from employees group by department_id)