Find next time business is open; mysql hours calculation - php

Question

I’m trying to figure out if a shop is currently within its opening hours, if not then select the next time its open.
Finally I need to be able to put the opening day as a specific date.
Can someone possible give me a tip how to construct this query?
Thanks in advance
CREATE TABLE `shop_hours` (
`id` int(11) NOT NULL,
`shop_id` int(11) unsigned NOT NULL,
`day_of_week` int(11) unsigned NOT NULL,
`open_time` time NOT NULL,
`close_time` time NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `shop_hours` (`id`, `shop_id`, `day_of_week`, `open_time`, `close_time`)
VALUES
(1, 1, 0, '08:00:00', '24:00:00'),
(2, 1, 1, '08:00:00', '24:00:00'),
(3, 1, 2, '08:00:00', '24:00:00'),
(4, 1, 3, '08:00:00', '24:00:00'),
(5, 1, 4, '08:00:00', '24:00:00'),
(6, 1, 5, '08:00:00', '24:00:00'),
(7, 1, 6, '08:00:00', '24:00:00');
Edit:
To clarify a little I'm not looking to find open shops, but only open hours for ONE specific shop. Based on the opening/closing hour, and what time it is now. I will generate some selectable timestamps incremented by 15 minutes.
E.g. if a shop has just closed (1PM), I will need to use the next open day's open/closing time instead. (the shop isn't necessarily open every day, could be closed Sundays).

Answer 1

To find out shop_id's, that is open for NOW()
SELECT *
FROM `shop_hours`
WHERE `day_of_week` = DATE_FORMAT(NOW(), '%w')
AND CURTIME() BETWEEN `open_time` AND `close_time`
Obsolete:
To find tomorrow's available open_times:
SELECT *
FROM `shop_hours`
WHERE `day_of_week` = DATE_FORMAT(DATE_ADD(NOW(), INTERVAL 1 DAY), '%w')
Edit 2:
To find next available open_times:
SELECT `shop_id`,
MIN(CAST(CONCAT(DATE(DATE_ADD(NOW(), INTERVAL ((7 + DATE_FORMAT(NOW(), '%w') - `day_of_week`) % 7) DAY)), ' ', `open_time`) AS DATETIME)) AS `next_open_datetime`
FROM `shop_hours`
GROUP BY `shop_id`
Edit:
DATE_FORMAT(*DATE*, '%w') uses the format 0 = Sunday ... 6 = Saturday
If you want to use the ISO format 1 = Monday ... 7 = Sunday in your day_of_week field, you should bind php's date('N') to your query (or use Mysql's if function IF(DATE_FORMAT(NOW(), '%w') = 0, 7, DATE_FORMAT(NOW(), '%w')), but that's ugly)

Answer 2

1) Check if shop is open. Result is empty, if shop is closed:
select * from shop_hours
where shop_id = $id
and dayofweek(curdate()) = day_of_week
and curtime() between open_time and close_time;
2) Find next open time:
(select open_time from shop_hours
where shop_id = $id and curtime() < open_time
and day_of_week >= dayofweek(curdate()))
union
(select open_time from shop_hours
where shop_id = $id and curtime() < open_time
order by day_of_week)
union
(select open_time from shop_hours
where shop_id = $id and curtime() > close_time
and day_of_week >= dayofweek(curdate()))
union
(select open_time from shop_hours
where shop_id = $id and curtime() > close_time
order by day_of_week)
limit 1;
Untested, but this should respect weekend wraparound and holes in the week (i.e. closed days).
Keep in mind, that dayofweek() numbers 1 = Sunday, 2 = Monday, ... If your table stores the weekdays in a different format, you must adjust the query accordingly.