SET SESSION group_concat_max_len = 1000000;;
SELECT
r.rental_date AS meet_time,
s.store_id,
GROUP_CONCAT(CONCAT(c.first_name, ' ', c.last_name) ORDER BY c.last_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
r.rental_date, s.store_id
HAVING
COUNT(c.customer_id) > 1
ORDER BY
meet_time, store_id;
;
show status like 'Last_query_cost';