如何完成这样的查询?(高分求教)
比如有一个字段为CreateDateTime,在这个表里有很多的记录,现在想查询出一组记录,符合这样的规则:
第N+1条记录中的CreateDateTime - 第N条记录中的CreateDateTime总是大于一个常数M?
------解决方案-------------------- select a.CreateDateTime from 表 a
right join
(
select top 1 aa.CreateDateTime from 表 aa
where aa.CreateDateTime < a.CreateDateTime
order by aa.CreateDateTime desc
) b
on b.CreateDateTime-a.CreateDateTime> M
------解决方案--------------------用里面的子查询来找到离N+1条记录最近的那条,作为第N条记录,然后用 right join做连接,条件是> M
------解决方案-------------------- 上面的不行,呵呵,用这个吧:
select a.CreateDateTime from 表 a
where not exists
(select 1 from 表 b
where b.CreateDateTime < a.CreateDateTime
and b.CreateDateTime > a.b.CreateDateTime-M )
------解决方案----------------------try
create table T(ID int, CreateDateTime datetime)
insert T select 2, '2007-1-2 10:10:000 '
insert T select 4, '2007-1-2 18:11:000 '
insert T select 5, '2007-1-4 19:20:000 '
insert T select 7, '2007-1-4 14:10:000 '
insert T select 10, '2007-1-4 10:16:000 '
insert T select 12, '2007-1-6 15:15:000 '
select * from T as A
where (select top 1 datediff(minute, A.CreateDateTime, CreateDateTime) from T where ID> A.ID order by ID)> 10
order by ID
------解决方案----------------------倘若CreateDateTime是datetime型的话,你做个类型转换就可以了啊
select a.CreateDateTime from 表 a
where not exists
(select 1 from 表 b
where cast(b.CreateDateTime as float) < cast(a.CreateDateTime as float)
and cast(b.CreateDateTime as float) > cast(a.CreateDateTime as float)-M )
------解决方案--------------------把表結構, 數據和想要的結果貼出來看看
------解决方案--------------------借用marco08(天道酬勤) 的表~
create table T(ID int, CreateDateTime datetime)
insert T select 2, '2007-1-2 10:10:000 '
insert T select 4, '2007-1-2 18:11:000 '
insert T select 5, '2007-1-4 19:20:000 '
insert T select 7, '2007-1-4 14:10:000 '
insert T select 10, '2007-1-4 10:16:000 '
insert T select 12, '2007-1-6 15:15:000 '
select * from T a RIGHT JOIN T b ON b.ID=(select min(ID) FROM T where ID> a.ID)
where DATEDIFF(day,a.CreateDateTime,b.CreateDateTime)> 1(> 1天,分钟、小时改 DATEDIFF(day,a.CreateDateTime,b.CreateDateTime)> 1)
------解决方案--------------------楼主是要两个相邻的时间段还是两个相邻的id?
------解决方案--------------------如果记录与时间都是递增的情况下,可以这样写
select *
from test t
where datediff(mi,(select max(CreateDateTime)from test where id <t.id),CreateDateTime) <60--60分的范围定义就行了
or
datediff(mi,CreateDateTime,(select min(CreateDateTime)from test where id> t.id)) <60--60分的范围定义就行了
------解决方案--------------------declare @test table (ID int, CreateDateTime datetime)
insert @test select 2, '2007-1-2 10:10:000 '
union all select 4, '2007-1-2 18:11:000 '
union all select 5, '2007-1-4 19:20:000 '
union all select 7, '2007-1-4 14:10:000 '
union all select 10, '2007-1-4 10:16:000 '
union all select 12, '2007-1-6 15:15:000 '