有如下表:A,
CUS_NO PRD_NO S_DD UP
====== ======= ========== =====
A BAD001 2007-12-01 2.0
A BAD001 2008-01-21 2.2
A BAD001 2008-02-15 2.1
B BAD001 2008-01-11 2.2
B BAD001 2008-02-22 2.3
C BAD001 2008-02-21 2.2
C BAD001 2008-02-23 2.1
A1 BAD002 2008-01-21 2.2
A2 BAD002 2008-01-21 2.3
A2 BAD002 2008-01-26 2.2
... ... ... ...
例如:希望将BAD001对应CUS_NO中取A,BAD001,2008-02-15(最近日期)的记录
所以,希望最终结果如下:
CUS_NO PRD_NO S_DD UP
====== ======= ========== =====
A BAD001 2008-02-15 2.1
B BAD001 2008-02-22 2.3
C BAD001 2008-02-23 2.1
A1 BAD002 2008-01-21 2.2
A2 BAD002 2008-01-26 2.2
个人感觉比较难描述,就将需求结果列示出来让大家容易看懂。
请专家、高手帮忙!重谢!
CUS_NO PRD_NO S_DD UP
====== ======= ========== =====
A BAD001 2007-12-01 2.0
A BAD001 2008-01-21 2.2
A BAD001 2008-02-15 2.1
B BAD001 2008-01-11 2.2
B BAD001 2008-02-22 2.3
C BAD001 2008-02-21 2.2
C BAD001 2008-02-23 2.1
A1 BAD002 2008-01-21 2.2
A2 BAD002 2008-01-21 2.3
A2 BAD002 2008-01-26 2.2
... ... ... ...
例如:希望将BAD001对应CUS_NO中取A,BAD001,2008-02-15(最近日期)的记录
所以,希望最终结果如下:
CUS_NO PRD_NO S_DD UP
====== ======= ========== =====
A BAD001 2008-02-15 2.1
B BAD001 2008-02-22 2.3
C BAD001 2008-02-23 2.1
A1 BAD002 2008-01-21 2.2
A2 BAD002 2008-01-26 2.2
个人感觉比较难描述,就将需求结果列示出来让大家容易看懂。
请专家、高手帮忙!重谢!
(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)
*/
select * from a t where not exists(select 1 from a where CUS_NO=t.CUS_NO and PRD_NO>t.PRD_NO)
--或者select * from a t where PRD_NO in(select max(PRD_NO) from a where CUS_NO=t.CUS_NO)
--或者select * from a t where (select count(distinct PRD_NO) from a where CUS_NO=t.CUS_NO and PRD_NO>t.PRD_NO)=1
INSERT INTO TB SELECT 'A' , 'BAD001' , '2007-12-01' , 2.0
INSERT INTO TB SELECT 'A' , 'BAD001' , '2008-01-21' , 2.2
INSERT INTO TB SELECT 'A' , 'BAD001' , '2008-02-15' , 2.1
INSERT INTO TB SELECT 'B' , 'BAD001' , '2008-01-11' , 2.2
INSERT INTO TB SELECT 'B' , 'BAD001' , '2008-02-22' , 2.3
INSERT INTO TB SELECT 'C' , 'BAD001' , '2008-02-21' , 2.2
INSERT INTO TB SELECT 'C' , 'BAD001' , '2008-02-23' , 2.1
INSERT INTO TB SELECT 'A1' , 'BAD002' , '2008-01-21' , 2.2
INSERT INTO TB SELECT 'A2' , 'BAD002' , '2008-01-21' , 2.3
INSERT INTO TB SELECT 'A2' , 'BAD002', '2008-01-26' , 2.2SELECT *
FROM tb A
WHERE NOT EXISTS(SELECT 1 FROM tb WHERE CUS_NO=A.CUS_NO AND S_DD>A.S_DD)DROP TABLE tb/*
CUS_NO PRD_NO S_DD UP
------ ------ ----------------------- ---------------------------------------
A BAD001 2008-02-15 00:00:00.000 2.10
B BAD001 2008-02-22 00:00:00.000 2.30
C BAD001 2008-02-23 00:00:00.000 2.10
A1 BAD002 2008-01-21 00:00:00.000 2.20
A2 BAD002 2008-01-26 00:00:00.000 2.20(5 row(s) affected)
*/
结帖方式:管理帖子->给分->输入密码->结帖.
谢谢.
create table tb(CUS_NO CHAR(2),PRD_NO CHAR(6),S_DD DATETIME,UP DECIMAL(10,2))
INSERT INTO TB SELECT 'A' , 'BAD001' , '2007-12-01' , 2.0
INSERT INTO TB SELECT 'A' , 'BAD001' , '2008-01-21' , 2.2
INSERT INTO TB SELECT 'A' , 'BAD001' , '2008-02-15' , 2.1
INSERT INTO TB SELECT 'B' , 'BAD001' , '2008-01-11' , 2.2
INSERT INTO TB SELECT 'B' , 'BAD001' , '2008-02-22' , 2.3
INSERT INTO TB SELECT 'C' , 'BAD001' , '2008-02-21' , 2.2
INSERT INTO TB SELECT 'C' , 'BAD001' , '2008-02-23' , 2.1
INSERT INTO TB SELECT 'A1' , 'BAD002' , '2008-01-21' , 2.2
INSERT INTO TB SELECT 'A2' , 'BAD002' , '2008-01-21' , 2.3
INSERT INTO TB SELECT 'A2' , 'BAD002', '2008-01-26' , 2.3 --多增加一条记录
INSERT INTO TB SELECT 'A2' , 'BAD002', '2008-01-26' , 2.2SELECT *
FROM tb A
WHERE NOT EXISTS(SELECT 1 FROM tb WHERE CUS_NO=A.CUS_NO AND S_DD>A.S_DD)DROP TABLE tb则存在问题
where a1.s_dd=(select max(a2.s_dd) from a a2 where a2.cus_no=a1.cus_no)
select * from A (此处添加a)where not exists(select * from A b where a.cus_no=b.cus_no and a.prd_no=b.prd_no and a.s_dd <b.s_dd) order by len(cus_no),cus_no
即可。谢谢你。
真不知道如何给分合适。
go
insert into A
select 'A','BAD001','2007-12-01',2.0
union select 'A','BAD001','2008-01-21',2.2
union select 'A','BAD001','2008-02-15',2.1
union select 'B','BAD001','2008-01-11',2.2
union select 'B','BAD001','2008-02-22',2.3
union select 'C','BAD001','2008-02-21',2.2
union select 'C','BAD001','2008-02-23',2.1
union select 'A1','BAD002','2008-01-21',2.2
union select 'A2','BAD002','2008-01-21',2.3
union select 'A2','BAD002','2008-01-26',2.3
union select 'A2','BAD002','2008-01-26',2.2
go
select * from A;
select cus_no,prd_no,s_dd,up
from A
where not exists(select * from A b where a.cus_no=b.cus_no and a.prd_no=b.prd_no and checksum(a.s_dd,a.up)>checksum(b.s_dd,b.up))
order by len(cus_no),cus_no
go
drop table A;
go(11 行受影响)
CUS_NO PRD_NO S_DD UP
-------- ---------- ----------------------- ---------------------------------------
A BAD001 2007-12-01 00:00:00.000 2.00
A BAD001 2008-01-21 00:00:00.000 2.20
A BAD001 2008-02-15 00:00:00.000 2.10
A1 BAD002 2008-01-21 00:00:00.000 2.20
A2 BAD002 2008-01-21 00:00:00.000 2.30
A2 BAD002 2008-01-26 00:00:00.000 2.20
A2 BAD002 2008-01-26 00:00:00.000 2.30
B BAD001 2008-01-11 00:00:00.000 2.20
B BAD001 2008-02-22 00:00:00.000 2.30
C BAD001 2008-02-21 00:00:00.000 2.20
C BAD001 2008-02-23 00:00:00.000 2.10(11 行受影响)cus_no prd_no s_dd up
-------- ---------- ----------------------- ---------------------------------------
A BAD001 2008-02-15 00:00:00.000 2.10
B BAD001 2008-02-22 00:00:00.000 2.30
C BAD001 2008-02-23 00:00:00.000 2.10
A1 BAD002 2008-01-21 00:00:00.000 2.20
A2 BAD002 2008-01-21 00:00:00.000 2.30(5 行受影响)
select cus_no,prd_no,s_dd,up
from A
where not exists(select * from A b where a.cus_no=b.cus_no and a.prd_no=b.prd_no and checksum(a.s_dd,a.up)>checksum(b.s_dd,b.up))
order by len(cus_no),cus_no
另外,你看看我9楼的解释.
不知道我是否在哪个地方少考虑了。呵呵
-----看错字段了。晕死.
select * from a t where not exists(select 1 from a where CUS_NO=t.CUS_NO and PRD_NO=t.PRD_NO and s_dd>t.S_DD)
--或者select * from a t where S_DD in(select max(S_DD) from a where CUS_NO=t.CUS_NO and PRD_NO=t.PRD_NO )
--或者select * from a t where (select count(distinct S_DD) from a where CUS_NO=t.CUS_NO and PRD_NO=t.PRD_NO and s_dd>t.S_DD)=1
结帖方式:管理帖子-> 给分-> 输入密码-> 结帖.
谢谢.请不要点帖子加分.
http://topic.csdn.net/u/20080110/19/7cb462f1-cac6-4c28-848e-0a879f4fd642.html
* 賤客無名
* 等 级:
发表于:2008-02-22 17:45:0316楼 得分:0
不好意思,我发贴时,没有去看我的分数,现在看才知道有60分,关键是我现在去结贴给分时,系统不让我结贴,请问:我该如何去操作,谢谢。
---------
楼主可能没注意,这个帖子实际是100分的帖子.
是这样子的.... 在帖子列表中找到本帖,看到帖子最后有“管理”了吗?
第一步: 用你可爱的鼠标点击一下。 进入帖子后找到23楼,一定要记住是23楼,看到得分后面有一个输入框没有?
第二步: 输入100 再往上找,可以看到在1楼的上面有一个广告,广告上面的左边有什么呀?
第三步: 在请输入密码后面的输入框内输入你的CSDN的登陆密码。 往右边看看,是不是有一个按钮呢?
第四步: 点击 结帖
from a t
where not exists(select 1
from a
where CUS_NO=t.CUS_NO and PRD_NO=t.PRD_NO and s_dd>t.S_DD)