mysql - 如何从可用时段和预订时段中查找空闲时段

Question

我有两张表，一张是可用时间段，另一张是预订时间段，其中包含开始日期时间和结束日期时间。我想退回空闲时间段。

表1

available_slots
start_datetime      |end_datetime
-----------------------------------------
2020-01-14 05:00:00 |2020-01-14 06:00:00
-----------------------------------------
2020-01-14 06:00:00 |2020-01-14 07:00:00
-----------------------------------------
2020-01-14 07:00:00 |2020-01-14 08:00:00
-----------------------------------------
2020-01-14 08:00:00 |2020-01-14 09:00:00
-----------------------------------------
2020-01-14 09:00:00 |2020-01-14 10:00:00
-----------------------------------------
2020-01-14 10:00:00 |2020-01-14 11:00:00
-----------------------------------------
2020-01-14 11:00:00 |2020-01-14 12:00:00
-----------------------------------------
2020-01-14 12:00:00 |2020-01-14 13:00:00
-----------------------------------------
2020-01-14 13:00:00 |2020-01-14 14:00:00
-----------------------------------------
2020-01-14 14:00:00 |2020-01-14 15:00:00
-----------------------------------------
2020-01-14 15:00:00 |2020-01-14 16:00:00
-----------------------------------------
2020-01-14 16:00:00 |2020-01-14 17:00:00

表2

booked_slots
start_datetime      |end_datetime
-----------------------------------------
2020-01-14 07:00:00 |2020-01-14 08:00:00
-----------------------------------------
2020-01-14 13:00:00 |2020-01-14 14:15:00
-----------------------------------------

结果应该是

Free slots
start_datetime      |end_datetime
-----------------------------------------
2020-01-14 05:00:00 |2020-01-14 06:00:00
-----------------------------------------
2020-01-14 06:00:00 |2020-01-14 07:00:00
-----------------------------------------
2020-01-14 08:00:00 |2020-01-14 09:00:00
-----------------------------------------
2020-01-14 09:00:00 |2020-01-14 10:00:00
-----------------------------------------
2020-01-14 10:00:00 |2020-01-14 11:00:00
-----------------------------------------
2020-01-14 11:00:00 |2020-01-14 12:00:00
-----------------------------------------
2020-01-14 12:00:00 |2020-01-14 13:00:00
-----------------------------------------
2020-01-14 15:00:00 |2020-01-14 16:00:00
-----------------------------------------
2020-01-14 16:00:00 |2020-01-14 17:00:00

Answer 1

SELECT table1.*
FROM table1 
WHERE NOT EXISTS (SELECT 1 
                  FROM table2  
                  WHERE table2.start_datetime = table1.start_datetime 
                  AND table2.end_datetime = table1.end_datetime);