Show only available time slots in select field - mysql

Question

I am working on a booking system where users can book certain services online. I am stuck on finding and displaying available time slots within a specific day. I know the length of the needed time slot is 1 hour and the business hours.
Is there a way to show time slots that has not yet been booked on a certain day and display only the available time slots that is available to be booked in a dropdown select form?
If a customer selects a specific day and clicks "Select Day" then it needs to query the DB and return the results.
My SQL structure is as follows
|id | title | start_time | end_time | booking_date |
| 1 | Name1 | 2022-05-12 08:00:00 | 2022-05-12 09:00:00 | 2022-05-12 |
| 2 | Name2 | 2022-05-12 10:00:00 | 2022-05-12 11:00:00 | 2022-05-12 |
| 3 | Name3 | 2022-05-12 13:00:00 | 2022-05-12 14:00:00 | 2022-05-12 |
| 4 | Name4 | 2022-05-12 14:00:00 | 2022-05-12 15:00:00 | 2022-05-12 |
as per above the select form should display the timeslots that is not already taken.
09:00 - 10:00
12:00 - 13:00
15:00 - 16:00

Answer 1

It would be something like:
select
id, title
from
<table>
where
start_time between '2022-05-12 00:00:00' and '2022-05-12 11:59:59'
and
booking_date is null
I don't know the name of your table, so you would need to replace <table> with that. I'm also assuming that "booking_date" will have a value to indicate that time slot has been reserved, that it's a date field, and it will be null if that slot hasn't been selected. However, booking_date could have a different purpose.

Answer 2

This is a lazy answer
(because I think just use SQL will do it, use subSelect and other function, but I don't know how to do, sorry.)
get today occupy time:
SELECT id, TIME(start_time) AS s_time FROM tablename
WHERE start_time >= '2022-05-12 00:00:00'
AND start_time < '2022-05-13 00:00:00'
diff time in php:
$sqlResult = []; // sql result
$timeAll = [
'00:00:00',
'01:00:00',
'02:00:00',
'03:00:00',
... // TODO: we need fill it
'23:00:00',
];
foreach ($sqlResult as $item) {
if (isset($timeAll[$item['s_time']])) {
unset($timeAll[$item['s_time']]);
}
}
return $timeAll;
// TODO: javascript or other client code can use it.
ref knowledge link:
MySQL SELECT WHERE datetime matches day (and not necessarily time)

Answer 3

If you choose 2022-05-26, and Peter is occupying room F25 from 2022-05-16 until 2022-05-29, it means the date you select must be out of this range.
So, the query below will only return rooms that were not booked on that day.
SELECT b.id, b.room_id as available_room FROM booking as b
WHERE(
unix_timestamp('$mydate')
NOT BETWEEN unix_timestamp(b.start_date)
AND unix_timestamp(b.end_time)
)
AND unix_timestamp(b.end_time) < unix_timestamp('$mydate');
Assuming $mydate is the variable that contains the date selected by the user, the above query will return rooms that will be available in the future on that particular day.