instruction: For those employees who was hired before 2002-06-21, find job_id and the average of department_id , and group by attribute job_id, and visualize them by a bar chart, I want to order by the X-axis from high to low.
response: SELECT JOB_ID, AVG(DEPARTMENT_ID) FROM employees WHERE HIRE_DATE < '2002-06-21' GROUP BY JOB_ID ORDER BY JOB_ID DESC