Edit As per Gordon, there is no need for a join if you don't require any of the job_form
specific fields. However, if you do (e.g. name or address), then:
SELECT jf.job_id,
jf.name,
MIN(ij.date) AS first_job_date,
MAX(ij.date) as last_job_date,
COUNT(*) as count_of_jobs
FROM job_form jf
INNER JOIN individual_job ij
ON jf.job_num = ij.job_num
GROUP BY jf.job_id, jf.name -- i.e. non-aggregated select fields here