Relationship between ost_task and thread

Can you please tell me the relationship between ost_task and ost_thread_entry.

I have a task which has had 2 updates

SELECT ot.id,
                     ot.created created,
                     ot.duedate duedate,
                     CASE
                         WHEN ot.closed IS NULL THEN "OPEN"
                         ELSE "CLOSED"
                     END AS case_status,
                     otc.title AS task,
                     od.name AS department,
                     CONCAT_WS( " ", os.firstname, os.lastname ) AS agent
                FROM ost_task ot
                     LEFT JOIN ost_task__cdata otc on ot.id=otc.task_id
                     LEFT JOIN ost_department od ON ot.dept_id=od.id
                     LEFT JOIN ost_staff os ON ot.staff_id=os.staff_id
                WHERE ot.id=2;

How do I join ost_thread_entry to get the updates.