By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
create table Appointment (
StartTime time not null,
EndTime time not null
);
insert Appointment values
('09:55', '10:55'),
('15:00', '16:00'),
('14:00', '15:00'),
('13:00', '13:30'),
('12:15', '16:00'),
('12:00', '16:00')
Records: 6 Duplicates: 0 Warnings: 0
select *
from Appointment
where starttime < '11:55' and '10:00' < endtime
| StartTime | EndTime |
|---|---|
| 09:55:00 | 10:55:00 |