А где сам запрос на выборку? Покажите запрос, подскажем, как улучшить.
Можно так (избавляемся от кучи JOINов и облегчаем жизнь СУБД):
SELECT
events.id,
events.e_name,
events.e_s_description,
events.e_type,
events_type.et_name,
(SELECT GROUP_CONCAT(events_dates.id SEPARATOR '|') FROM events_dates WHERE events_dates.ed_event_id = events.id AND events_dates.ed_is_active = '1') AS ed_ids,
(SELECT GROUP_CONCAT(events_dates.ed_date_start SEPARATOR '|') FROM events_dates WHERE events_dates.ed_event_id = events.id AND events_dates.ed_is_active = '1') AS ed_date_start,
(SELECT GROUP_CONCAT(events_projects.ep_proj_id SEPARATOR '|') FROM events_projects WHERE events_projects.ep_event_id = events.id AND ep_is_active = '1') AS ep_proj_id,
(SELECT GROUP_CONCAT(projects.pr_name SEPARATOR '|') FROM projects WHERE projects.id IN (SELECT events_projects.ep_proj_id FROM events_projects WHERE events_projects.ep_event_id = events.id AND ep_is_active = '1')) AS pr_name,
(SELECT GROUP_CONCAT(events_research_directions.erd_res_dir_id SEPARATOR '|') FROM events_research_directions WHERE events_research_directions.erd_event_id = events.id AND erd_is_active = '1') AS erd_res_dir_id
(SELECT GROUP_CONCAT(research_direction.rd_name SEPARATOR '|' ) FROM research_direction WHERE research_direction.id IN (SELECT events_research_directions.erd_res_dir_id FROM events_research_directions WHERE events_research_directions.erd_event_id = events.id AND erd_is_active = '1')) AS rd_name
FROM events
LEFT OUTER JOIN events_type ON events_type.id = events.e_type
WHERE
events.e_is_active = '1'
AND events.e_type = 1
ORDER BY events.e_date_add DESC