SET SESSION group_concat_max_len = 1000000;;
SELECT
r.rental_date AS meet_time,
s.store_id,
GROUP_CONCAT(
CONCAT(c.last_name, ' ', c.first_name)
ORDER BY c.last_name, c.first_name
SEPARATOR ','
) AS customers
FROM rental r
JOIN customer c ON r.customer_id = c.customer_id
JOIN staff s ON r.staff_id = s.staff_id
GROUP BY s.store_id, r.rental_date
HAVING COUNT(DISTINCT r.customer_id) >= 2
ORDER BY meet_time, s.store_id;
;
show status like 'Last_query_cost';