我认为您可能通过为不同长度的时隙设置多个表来使这一点过于复杂。当您想以 15 分钟而不是 30 分钟为间隔时会发生什么?当您想要允许 90 分钟的约会时会发生什么?如果安排这些约会的办公室在不同的日子有不同的时间会怎样?
我在下面提出的解决方案使用一张表来存储约会,就是这样。当您需要给定日期的可用约会列表时,显示的其余逻辑可以轻松进入存储过程或调用的东西。希望评论足以解释发生了什么。
-- Sample data from the question.
declare @Appointment table
(
[ID] bigint not null identity(1, 1), -- Primary key.
[BookedDate] date not null, -- The date of the appointment.
[Time] time(0) not null, -- The start time of the appointment.
[Duration] int not null -- The length of the appointment in minutes.
);
insert @Appointment
([BookedDate], [Time], [Duration])
values
('2014-04-15', '09:00', 60),
('2014-04-15', '10:00', 30),
('2014-04-15', '17:00', 60),
('2014-04-15', '18:30', 30);
-- @StartTime is the time the office opens on the desired date.
-- @EndTime is the time the office closes on the desired date.
-- @Interval is the number of minutes that separate potential appointment times.
-- @DesiredDate is the date on which an appointment is requested.
-- @DesiredLength is the length of the requested appointment in minutes.
declare @StartTime time(0) = '09:00';
declare @EndTime time(0) = '21:00';
declare @Interval int = 30;
declare @DesiredDate date = '2014-04-15';
declare @DesiredLength int = 30;
-- This CTE enumerates all potential timeslots on the @DesiredDate given the above data.
with [TimeSlotCTE] as
(
-- Base case: the first appointment slot of the day.
select
[From] = @StartTime,
[To] = dateadd(minute, @DesiredLength, @StartTime)
union all
-- Recursive case: create a subsequent appointment slot as long as doing so won't
-- take us past the office's closing time.
select
dateadd(minute, @Interval, [From]),
dateadd(minute, @Interval, [To])
from
[TimeSlotCTE]
where
dateadd(minute, @Interval, [To]) <= @EndTime
)
-- Finally, we simply select every time slot defined above for which there does not
-- yet exist an overlapping appointment on the requested date.
select
[T].[From],
[T].[To],
[Available] =
case when exists
(
select 1 from @Appointment [A]
where
-- Forgot this line the first time around!
[A].[BookedDate] = @DesiredDate and
[A].[Time] < [T].[To] and
dateadd(minute, [A].[Duration], [A].[Time]) > [T].[From]
)
then 'No' else 'Yes' end
from
[TimeSlotCTE] [T];
如果我使用以下代码运行上述代码,则输出@DesiredLength = 30
如下:
From To Available
09:00:00 09:30:00 No
09:30:00 10:00:00 No
10:00:00 10:30:00 No
10:30:00 11:00:00 Yes
11:00:00 11:30:00 Yes
11:30:00 12:00:00 Yes
12:00:00 12:30:00 Yes
12:30:00 13:00:00 Yes
13:00:00 13:30:00 Yes
13:30:00 14:00:00 Yes
14:00:00 14:30:00 Yes
14:30:00 15:00:00 Yes
15:00:00 15:30:00 Yes
15:30:00 16:00:00 Yes
16:00:00 16:30:00 Yes
16:30:00 17:00:00 Yes
17:00:00 17:30:00 No
17:30:00 18:00:00 No
18:00:00 18:30:00 Yes
18:30:00 19:00:00 No
19:00:00 19:30:00 Yes
19:30:00 20:00:00 Yes
20:00:00 20:30:00 Yes
20:30:00 21:00:00 Yes
这是与@DesiredLength = 60
:
From To Available
09:00:00 10:00:00 No
09:30:00 10:30:00 No
10:00:00 11:00:00 No
10:30:00 11:30:00 Yes
11:00:00 12:00:00 Yes
11:30:00 12:30:00 Yes
12:00:00 13:00:00 Yes
12:30:00 13:30:00 Yes
13:00:00 14:00:00 Yes
13:30:00 14:30:00 Yes
14:00:00 15:00:00 Yes
14:30:00 15:30:00 Yes
15:00:00 16:00:00 Yes
15:30:00 16:30:00 Yes
16:00:00 17:00:00 Yes
16:30:00 17:30:00 No
17:00:00 18:00:00 No
17:30:00 18:30:00 No
18:00:00 19:00:00 No
18:30:00 19:30:00 No
19:00:00 20:00:00 Yes
19:30:00 20:30:00 Yes
20:00:00 21:00:00 Yes
像这样的东西对你有用吗?