select * from t_houseSource t where loginID in(select top 4 from t_houseSource where loginID=t.loginID)
select * from t_houseSource t where loginID in(select top 4 from t_houseSource where loginID=t.loginID)
select * from t_houseSource t where loginID in(select top 4 from t_houseSource where loginID=t.loginID)
/*
数据如下：
name val memo
a 2 a2(a的第二个值)
a 1 a1--a的第一个值
a 3 a3:a的第三个值
b 1 b1--b的第一个值
b 3 b3:b的第三个值
b 2 b2b2b2b2
b 4 b4b4
b 5 b5b5b5b5b5
*/
--创建表并插入数据：
create table tb(name varchar(10),val int,memo varchar(20))
insert into tb values('a', 2, 'a2(a的第二个值)')
insert into tb values('a', 1, 'a1--a的第一个值')
insert into tb values('a', 3, 'a3:a的第三个值')
insert into tb values('b', 1, 'b1--b的第一个值')
insert into tb values('b', 3, 'b3:b的第三个值')
insert into tb values('b', 2, 'b2b2b2b2')
insert into tb values('b', 4, 'b4b4')
insert into tb values('b', 5, 'b5b5b5b5b5')
go--一、按name分组取val最大的值所在行的数据。
--方法1：
select a.* from tb a where val = (select max(val) from tb where name = a.name) order by a.name
--方法2：
select a.* from tb a where not exists(select 1 from tb where name = a.name and val > a.val)
--方法3：
select a.* from tb a,(select name,max(val) val from tb group by name) b where a.name = b.name and a.val = b.val order by a.name
--方法4：
select a.* from tb a inner join (select name , max(val) val from tb group by name) b on a.name = b.name and a.val = b.val order by a.name
--方法5
select a.* from tb a where 1 > (select count(*) from tb where name = a.name and val > a.val ) order by a.name
/*
name val memo
---------- ----------- --------------------
a 3 a3:a的第三个值
b 5 b5b5b5b5b5
*/--二、按name分组取val最小的值所在行的数据。
--方法1：
select a.* from tb a where val = (select min(val) from tb where name = a.name) order by a.name
--方法2：
select a.* from tb a where not exists(select 1 from tb where name = a.name and val < a.val)
--方法3：
select a.* from tb a,(select name,min(val) val from tb group by name) b where a.name = b.name and a.val = b.val order by a.name
--方法4：
select a.* from tb a inner join (select name , min(val) val from tb group by name) b on a.name = b.name and a.val = b.val order by a.name
--方法5
select a.* from tb a where 1 > (select count(*) from tb where name = a.name and val < a.val) order by a.name
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值
*/--三、按name分组取第一次出现的行所在的数据。
select a.* from tb a where val = (select top 1 val from tb where name = a.name) order by a.name
/*
name val memo
---------- ----------- --------------------
a 2 a2(a的第二个值)
b 1 b1--b的第一个值
*/--四、按name分组随机取一条数据。
select a.* from tb a where val = (select top 1 val from tb where name = a.name order by newid()) order by a.name
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 5 b5b5b5b5b5
*/--五、按name分组取最小的两个(N个)val
select a.* from tb a where 2 > (select count(*) from tb where name = a.name and val < a.val ) order by a.name,a.val
select a.* from tb a where val in (select top 2 val from tb where name=a.name order by val) order by a.name,a.val
select a.* from tb a where exists (select count(*) from tb where name = a.name and val < a.val having Count(*) < 2) order by a.name
/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
a 2 a2(a的第二个值)
b 1 b1--b的第一个值
b 2 b2b2b2b2
*/--六、按name分组取最大的两个(N个)val
select a.* from tb a where 2 > (select count(*) from tb where name = a.name and val > a.val ) order by a.name,a.val
select a.* from tb a where val in (select top 2 val from tb where name=a.name order by val desc) order by a.name,a.val
select a.* from tb a where exists (select count(*) from tb where name = a.name and val > a.val having Count(*) < 2) order by a.name
/*
name val memo
---------- ----------- --------------------
a 2 a2(a的第二个值)
a 3 a3:a的第三个值
b 4 b4b4
b 5 b5b5b5b5b5
*/最后2种？
create table t_housesource(loginID int, countyid varchar(02),publictime datetime)
insert into t_housesource select 1,'A','2008-1-1'
insert into t_housesource select 2,'A','2008-1-2'
insert into t_housesource select 3,'A','2008-1-3'
insert into t_housesource select 4,'A','2008-1-4'
insert into t_housesource select 5,'A','2008-1-5'
insert into t_housesource select 6,'B','2008-1-6'
insert into t_housesource select 7,'B','2008-1-7'
insert into t_housesource select 8,'B','2008-1-8'
insert into t_housesource select 9,'B','2008-1-9'
insert into t_housesource select 10,'B','2008-1-10'
insert into t_housesource select 11,'B','2008-1-11'insert into t_housesource select 12,'C','2008-1-16'
insert into t_housesource select 13,'C','2008-1-15'
insert into t_housesource select 14,'C','2008-1-14'
insert into t_housesource select 15,'C','2008-1-13'
insert into t_housesource select 16,'C','2008-1-12'--時間倒序
select a.* from t_housesource a
where loginid in
(select top 4 loginid from t_housesource where countyid=a.countyid order by publictime desc)
/*
1 A 2008-01-01 00:00:00.000
2 A 2008-01-02 00:00:00.000
3 A 2008-01-03 00:00:00.000
4 A 2008-01-04 00:00:00.000
6 B 2008-01-06 00:00:00.000
7 B 2008-01-07 00:00:00.000
8 B 2008-01-08 00:00:00.000
9 B 2008-01-09 00:00:00.000
13 C 2008-01-15 00:00:00.000
14 C 2008-01-14 00:00:00.000
15 C 2008-01-13 00:00:00.000
16 C 2008-01-12 00:00:00.000*/drop table t_housesource
select * from t_houseSource t where loginID in(select top 4 from t_houseSource where countyid=t.countyid)
我想得到当前每一个片区最新发布房源信息的前四个loginid,假如有三个执行片区的话,结果应为12条记录.谢谢!select t.* from t_housesource t
where publicTime in (select top 4 publicTime from t_housesource where countyid = t.countyid order by publicTime desc)
select a.countyid,b.loginID
from houseSource a,
(select t.* from houseSource t where publicTime in (select top 4 loginID from houseSource where countyid= t.countyid order by publicTime desc)
) b
where a.countyid=b.countyid
--這個才是倒序的
2 A 2008-01-02 00:00:00.000
3 A 2008-01-03 00:00:00.000
4 A 2008-01-04 00:00:00.000
5 A 2008-01-05 00:00:00.000
8 B 2008-01-08 00:00:00.000
9 B 2008-01-09 00:00:00.000
10 B 2008-01-10 00:00:00.000
11 B 2008-01-11 00:00:00.000
12 C 2008-01-16 00:00:00.000
13 C 2008-01-15 00:00:00.000
14 C 2008-01-14 00:00:00.000
15 C 2008-01-13 00:00:00.000
---------------------------------------
可你这个表中，根本没有涉及到人噢？？
select m.* from
(
select countyid , loginID , publicTime = max(publicTime) from tb group by countyid , loginID
) m where publicTime in (select top 4 publicTime from
(
select countyid , loginID , publicTime = max(publicTime) from tb group by countyid , loginID
) n where n.countyid = m.countyid order by publicTime desc
)