What are the department ids for departments that have someone with the first name Clara?
select department_id from employees where first_name = "Clara"
What is all the information about employees in those departments?
select * from employees where department_id = (select department_id from employees where first_name = "Clara")
What are the full names and hire dates of those employees?
select first_name, last_name, hire_date from employees where department_id = (select department_id from employees where first_name = "Clara")