表:
ID,类型,时间,其它1 A 2012-04-23 18:00:00
2 A 2012-04-24 18:00:00
3 A 2012-04-25 18:00:00
5 B 2012-04-23 18:00:00
6 B 2012-04-24 18:00:00
7 C 2012-04-25 18:00:00
8 C 2012-04-23 18:00:00
我要按分类查询,得到 A,B,C中,时间最大的记录各1条。我要的结果:3 A 2012-04-25 18:00:00
6 B 2012-04-24 18:00:00
7 C 2012-04-25 18:00:00这语法这么写?
ID,类型,时间,其它1 A 2012-04-23 18:00:00
2 A 2012-04-24 18:00:00
3 A 2012-04-25 18:00:00
5 B 2012-04-23 18:00:00
6 B 2012-04-24 18:00:00
7 C 2012-04-25 18:00:00
8 C 2012-04-23 18:00:00
我要按分类查询,得到 A,B,C中,时间最大的记录各1条。我要的结果:3 A 2012-04-25 18:00:00
6 B 2012-04-24 18:00:00
7 C 2012-04-25 18:00:00这语法这么写?
select 类型,
时间
from 表 t
where id in(select top 1 id from 表 where 类型=t.类型 order by 时间 desc)
go
create table [TB] (ID int,类型 nvarchar(2),时间 datetime,其它 sql_variant)
insert into [TB]
select 1,'A','2012-04-23 18:00:00',null union all
select 2,'A','2012-04-24 18:00:00',null union all
select 3,'A','2012-04-25 18:00:00',null union all
select 5,'B','2012-04-23 18:00:00',null union all
select 6,'B','2012-04-24 18:00:00',null union all
select 7,'C','2012-04-25 18:00:00',null union all
select 8,'C','2012-04-23 18:00:00',nullselect * from [TB]
select distinct B.ID,B.类型,B.时间
from TB A
cross apply(select top 1 ID,类型,时间 from TB where 类型 = A.类型 order by 时间 desc) B
/*
3 A 2012-04-25 18:00:00.000
6 B 2012-04-24 18:00:00.000
7 C 2012-04-25 18:00:00.000*/
as(select ROW_NUMBER() over(PARTITION by 类型 order by 时间 desc )as nn ,* from TB)select ID,类型,时间 from TT where nn = 1