###HUMAN: For those employees who was hired before 2002-06-21, draw a bar chart about the distribution of job_id and the amount of job_id , and group by attribute job_id, rank in descending by the the number of job id., ###ASSISTANT: SELECT JOB_ID, COUNT(JOB_ID) FROM employees WHERE HIRE_DATE < '2002-06-21' GROUP BY JOB_ID ORDER BY COUNT(JOB_ID) DESC