求语句

表格如下：

id time num
a 9:00 22
a 10:00 2
a 11:00 20
a 12:00 9
a 13:00 18
.. . ......

a 16:00 15

b 9:00 22
b 10:00 2
b 11:00 20
b 12:00 9
b 13:00 18
.. . ......

b 16:00 14

c 9:00 11
.. . ......
.. . ......
.. . ......
.. . ......

每小时测量一次数据
a 和 b 在 9:00--15:00 期间的每一个数字完全相同，但是16:00以后就不相同了，

如何找出 9:00/ 16:00这两个时间点？




 

什么意思啊？

SQL code

if object_id('tb') is not null
   drop table tb
go
create table tb
(
 id varchar(10),
 time datetime,
 num int
)
go
insert into tb
select 'a','9:00',22 union all
select 'a','10:00',2 union all
select 'a','11:00',20 union all
select 'a','12:00',9 union all
select 'a','13:00',18 union all
select 'a','14:00',15 union all
select 'a','15:00',14 union all
select 'a','16:00',12 union all
select 'a','17:00',10 union all
select 'a','18:00',9 union all

select 'b','9:00',22 union all
select 'b','10:00',2 union all
select 'b','11:00',20 union all
select 'b','12:00',9 union all
select 'b','13:00',18 union all
select 'b','14:00',15 union all
select 'b','15:00',14 union all
select 'b','16:00',10 union all
select 'b','17:00',19 union all
select 'b','18:00',30
go
select convert(varchar(5),a1.time,108),convert(varchar(5),a2.time,108) from
(
select top 1 t1.time from (select * from tb where id='a') t1 inner join (select * from tb where id='b') t2 on t1.time=t2.time and t1.num=t2.num order by time
)a1
cross apply
(
select top 1 t1.time from (select * from tb where id='a') t1 inner join (select * from tb where id='b') t2 on t1.time=t2.time and t1.num<>t2.num order by time
)a2
/*
----- -----
09:00 16:00

(1 行受影响)

*/