如何在sql查询中检查所有时隙

我必须编写查询以根据时间段更新roomid比较房间

我有这个表格数据

customerid    appointmentfrom            appointmentto               roomid
----------------------------------------------------------------------------   
    1         2020-07-18 10:00:00.000    2020-07-18 11:30:00.000        1
    2         2020-07-18 10:30:00.000    2020-07-18 11:15:00.000        2
    3         2020-07-18 11:15:00.000    2020-07-18 11:59:00.000        2

我不应该允许customerid 1将其roomid更新为2，因为roomid 2已在该时段预订

---

customerid 1正在尝试将roomid更新为2，但我需要检查他正在预订的约会From和AppointTo是否可用

您的问题没有说明如何获取输入或如何处理禁止的更新抛出错误？。此解决方案将参数作为输入，不允许更新时不执行任何操作。我还包括对客户何时有多个约会的支持

where子句使用仅选择可更新记录

-- create example
declare @data table
(
    customerid int,
    appointmentfrom datetime,
    appointmentto datetime,
    roomid int
);

insert into @data (customerid, appointmentfrom, appointmentto, roomid) values
(1, '2020-07-18 10:00:00.000', '2020-07-18 11:30:00.000', 1),
(2, '2020-07-18 10:30:00.000', '2020-07-18 11:15:00.000', 2),
(3, '2020-07-18 11:15:00.000', '2020-07-18 11:59:00.000', 2);


-- solution (with parameters)
declare @customerid int = 1;                                    -- specify customer
declare @appointmentfrom datetime = '2020-07-18 10:00:00.000';  -- specify customer appointment
declare @newroomid int = 2;                                     -- specify target room

update d
set d.roomid = @newroomid
from @data d
where d.customerid = @customerid            -- select customer...
  and d.appointmentfrom = @appointmentfrom  -- ... and his appointment
  -- look for any unwanted overlapping meetings on the target room
  and not exists (  select top 1 'x'
                    from @data d2
                    where d2.roomid = @newroomid
                      and d2.appointmentto > d.appointmentfrom
                      and d2.appointmentfrom < d.appointmentto );
-- (0 rows affected)

---

抱歉roomid是另一个值为1,2,2的列。您是否也使用SQL Server 2008或2012？2008是完全不受支持的，因此如果您正在使用它，您现在应该真正查看升级路径。@AJMi，可能会有帮助。这一条不会有帮助，因为我必须比较是否已在客户1试图将其房间号从上午10点更新为上午11点30分的这段时间内预订了约会，如果预订了，我不允许更新