SELECT task.*,a.users_login AS createuser,a.users_id AS createuser_id,b.users_login AS respuser,b.users_id AS respusers_id,b.users_role,
contact.*,point.*,company.*,d.sum_time,d.sum_text,task_status.*
FROM task
LEFT JOIN users a ON task_user_id=a.users_id
LEFT JOIN users b ON task_resp_user_id=b.users_id
LEFT JOIN `contact` ON contact_id=task_contact_id
LEFT JOIN `point` ON task_point_id=point_id
LEFT JOIN `company` ON task_company_id=company_id
LEFT JOIN `task_status` ON task_status_id = task_status
-- Используем соединение с подзапросом, который фильтрует данные по comment_task_id
LEFT JOIN (SELECT comment_task_id,sum(comment_time) AS sum_time,GROUP_CONCAT(comment_text) AS sum_text FROM `comment` WHERE comment_task_id IN (SELECT task_id FROM task WHERE task_resp_user_id = '13' AND task_status = '1') GROUP BY comment_task_id ) d ON d.comment_task_id = task_id
WHERE concat(contact_tel,' ',contact_name,' ',contact_sname,' ',contact_surname) LIKE '%%'
AND CONCAT(point_id,' ',point_name,' ',point_zona,' ',point_city,' ',point_street,' ',point_dom) LIKE '%%'
and task_resp_user_id = '13'
AND task_status = '1'
order by task_id desc LIMIT 100