SQL/Mysql query available dates and times in database - mysql

Question

I need some help querying my calendar/dates table
Scenario: I have a "calendar" table with dates and times (see below), users will set their available dates, usually day by day with available time slots for each day. So my table looks like this:
+------+------------+---------------------+---------------------+
| ID | user_id | start_date | end_date |
+------+------------+---------------------+---------------------+
| 1 | 1 | 2016-09-01 08:00:00 | 2016-09-01 16:00:00 |
| 2 | 1 | 2016-09-03 00:00:00 | 2016-09-03 23:59:59 |
| 3 | 1 | 2016-09-04 00:00:00 | 2016-09-04 16:00:00 |
| 4 | 1 | 2016-09-05 08:00:00 | 2016-09-05 16:00:00 |
| 5 | 2 | 2016-09-05 08:00:00 | 2016-09-05 16:00:00 |
| 6 | 2 | 2016-09-07 08:00:00 | 2016-09-07 16:00:00 |
| 7 | 2 | 2016-09-08 08:00:00 | 2016-09-08 16:00:00 |
| 8 | 2 | 2016-09-08 18:00:00 | 2016-09-08 22:00:00 |
+------+------------+---------------------+---------------------+
We have 2 users here so I want the following:
If I search for start_date = 2016-09-05 08:00:00 and end_date = 2016-09-05 16:00:00 it should return user 1 and 2. Since both of them has an entry with these dates. Same goes as well if start_date = 2016-09-05 09:00:00 and end_date = 2016-09-05 15:00:00, this should as well return both users since the time im searching for is between the time slots as shown in the example.
Second scenario is a little bit more tricky, If user search for start_date = 2016-09-03 08:00:00 and end_date = 2016-09-04 16:00:00 i want the query to check the following:
see if the user is available each day at these times.
so in this case, is the user available on 2016-09-03 between 08:00:00 and 16:00:00 and as well on 2016-09-04 between 08:00:00 and 16:00:00.
In the example over this should return user 1.
Im open for suggestion on re-designed my schema if needed.
Hope some can help me with this.

Answer 1

DEMO include some aditional code comment, and show how the query evolve . Also I add another row for user_id = 2 to show how only match one of the two days in the range.
SELECT U.`user_id`
FROM (
select a.selectDate,
CONCAT(a.selectDate, ' ', time(#s_date)) as start_time,
CONCAT(a.selectDate, ' ', time(#s_date)) as end_time
from (
select '1900-01-01' + INTERVAL (a.a + (10 * b.a) + (100 * c.a) + (1000 * d.a) + (10000 * e.a)) DAY as selectDate
from (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as a
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as b
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as c
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as d
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as e
) a
CROSS JOIN (SELECT #s_date := '2016-09-03 08:00:00', #e_date := '2016-09-04 16:00:00') par
-- CROSS JOIN (SELECT #s_date := '2016-09-05 08:00:00', #e_date := '2016-09-05 16:00:00') par
-- CROSS JOIN (SELECT #s_date := '2016-09-05 09:00:00', #e_date := '2016-09-05 15:00:00') par
WHERE selectDate BETWEEN date(#s_date)
AND date(#e_date)
) D
CROSS JOIN (SELECT DISTINCT `user_id` FROM Table1) U
LEFT JOIN Table1 T
ON U.`user_id` = T.`user_id`
AND D.start_time <= T.`end_date`
AND D.end_time >= T.`start_date`
GROUP BY U.`user_id`
HAVING COUNT(U.`user_id`) = COUNT(T.`user_id`);
OUTPUT
Step 1: create a list of dates, in this case 273 years
Step 2: select all dates between the range define in the parameters, also include the time window to each date.
Step 3: join all together to see what dates have user in that time window
Step 4: select only user with a time window for all dates