stationID time waterbase
1974 2008-03-25 14:05:00.000 -9.3800000000000008
1974 2008-03-25 14:00:00.000 -9.3100000000000005
2107 2008-04-15 23:45:00.000 -0.26000000000000001
2107 2008-04-16 11:35:00.000 -0.2199999
1995 2007-04-10 20:00:00.000 0.0
2008 2006-10-18 09:10:00.000 0.0
1434 2008-04-16 11:45:00.000 0.02
1430 2008-04-15 16:15:00.000 4.0000000000000001E-2
1430 2008-04-15 16:20:00.000 5.0000000000000003E-2
1393 2008-04-16 08:30:00.000 8.0000000000000002E-2
4797 2007-08-27 18:20:00.000 8.0000000000000002E-2
怎么查time最大的且按stationID分组的记录?
多谢!
1974 2008-03-25 14:05:00.000 -9.3800000000000008
1974 2008-03-25 14:00:00.000 -9.3100000000000005
2107 2008-04-15 23:45:00.000 -0.26000000000000001
2107 2008-04-16 11:35:00.000 -0.2199999
1995 2007-04-10 20:00:00.000 0.0
2008 2006-10-18 09:10:00.000 0.0
1434 2008-04-16 11:45:00.000 0.02
1430 2008-04-15 16:15:00.000 4.0000000000000001E-2
1430 2008-04-15 16:20:00.000 5.0000000000000003E-2
1393 2008-04-16 08:30:00.000 8.0000000000000002E-2
4797 2007-08-27 18:20:00.000 8.0000000000000002E-2
怎么查time最大的且按stationID分组的记录?
多谢!
(爱新觉罗.毓华 2007-10-23于浙江杭州)
/*
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
*/
--七,如果整行数据有重复,所有的列都相同。
/*
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 1 a1--a的第一个值
a 3 a3:a的第三个值
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
*/
--在sql server 2000中只能用一个临时表来解决,生成一个自增列,先对val取最大或最小,然后再通过自增列来取数据。
--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', 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('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')
goselect * , px = identity(int,1,1) into tmp from tbselect m.name,m.val,m.memo from
(
select t.* from tmp t where val = (select min(val) from tmp where name = t.name)
) m where px = (select min(px) from
(
select t.* from tmp t where val = (select min(val) from tmp where name = t.name)
) n where n.name = m.name)drop table tb,tmp/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值(2 行受影响)
*/
--在sql server 2005中可以使用row_number函数,不需要使用临时表。
--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', 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('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')
goselect m.name,m.val,m.memo from
(
select * , px = row_number() over(order by name , val) from tb
) m where px = (select min(px) from
(
select * , px = row_number() over(order by name , val) from tb
) n where n.name = m.name)drop table tb/*
name val memo
---------- ----------- --------------------
a 1 a1--a的第一个值
b 1 b1--b的第一个值(2 行受影响)
*/
where time=(select max(time) from tablename where stationid=a.stationid)
if object_id('tempdb.dbo.#T') is not null drop table #T
create table #T (stationID int,time datetime,waterbase float)
insert into #T
select 1974,'2008-03-25 14:05:00.000',-9.3800000000000008 union all
select 1974,'2008-03-25 14:00:00.000',-9.3100000000000005 union all
select 2107,'2008-04-15 23:45:00.000',-0.26000000000000001 union all
select 2107,'2008-04-16 11:35:00.000',-0.2199999 union all
select 1995,'2007-04-10 20:00:00.000',0.0 union all
select 2008,'2006-10-18 09:10:00.000',0.0 union all
select 1434,'2008-04-16 11:45:00.000',0.02 union all
select 1430,'2008-04-15 16:15:00.000',4.0000000000000001E-2 union all
select 1430,'2008-04-15 16:20:00.000',5.0000000000000003E-2 union all
select 1393,'2008-04-16 08:30:00.000',8.0000000000000002E-2 union all
select 4797,'2007-08-27 18:20:00.000',8.0000000000000002E-2select * from #T t where time=(select max(time) from #T where stationID=t.stationID) order by 1/*
stationID time waterbase
----------- ----------------------- ----------------------
1393 2008-04-16 08:30:00.000 0.08
1430 2008-04-15 16:20:00.000 0.05
1434 2008-04-16 11:45:00.000 0.02
1974 2008-03-25 14:05:00.000 -9.38
1995 2007-04-10 20:00:00.000 0
2008 2006-10-18 09:10:00.000 0
2107 2008-04-16 11:35:00.000 -0.2199999
4797 2007-08-27 18:20:00.000 0.08
*/
declare @tb table (dt datetime,stockid char(6),fvol numeric(20,5))
insert into @tb select '2008-3-11','000800',289928.4375
insert into @tb select '2008-2-22','000800',503016.1875
insert into @tb select '2008-2-25','000800',-10095.21582
insert into @tb select '2008-2-26','000800',-36981.878906
insert into @tb select '2008-2-27','000800',644.995361
insert into @tb select '2008-2-28','000800',2198.187988
insert into @tb select '2008-2-29','000800',5654.983398
insert into @tb select '2008-3-3','000800', 5546.563965 insert into @tb select '2008-3-2','600000',-24493.21875
insert into @tb select '2008-2-22','600000',550059.6875
insert into @tb select '2008-2-25','600000',-18295.4375
insert into @tb select '2008-2-26','600000', -81992.4375
insert into @tb select '2008-2-27','600000',84372.671875
insert into @tb select '2008-2-28','600000',-10039.753906
insert into @tb select '2008-2-29','600000',-715.375
insert into @tb select '2008-3-3','600000',26328.328125 select * From
(
select top 10 stockid, (dt) ,fvol
from
@tb
group by stockid ,dt ,fvol
order by max(dt) desc
)c
order by stockid ,dt