导航
  • 主页
  • 基础类
  • 应用实例
  • 新技术前沿

?求一SQL文,谢谢!

WAWQ 2007-12-24 09:51:57
已知数据库结构如下:
id A B C
1 1 1 10
2 1 2 20
3 2 1 100
4 2 2 200
5 3 2 1000
6 3 3 2000
7 3 4 3000

查询结果为:
id A B C
1 1 1 10
3 2 1 100
5 3 2 1000

即按照A进行分组,取B最小的时候C的值,谢谢!!!
...全文
67 点赞 收藏 11
写回复
11 条回复
切换为时间正序
请发表友善的回复…
发表回复
areswang 2007-12-24
create table tb(id int,A int,B int,C int)
insert into tb values(1, 1, 1,10)
insert into tb values(2, 1, 2,20)
insert into tb values(3, 2, 1,100)
insert into tb values(4, 2, 2,200)
insert into tb values(5, 3, 2,1000)
insert into tb values(6, 3, 3,2000)
insert into tb values(7, 3, 4,3000)

go

select a.* from tb a where not exists(select 1 from tb where a = a.a and b < a.b )

drop table tb
--------------------
id A B C
1 1 1 10
3 2 1 100
5 3 2 1000
回复
中国风 2007-12-24
declare @T table(id int,   A int,   B int,  C int)
insert @T select 1, 1, 1, 10
insert @T select 2, 1, 2, 20
insert @T select 3, 2, 1, 100
insert @T select 4, 2, 2, 200
insert @T select 5, 3, 2, 1000
insert @T select 6, 3, 3, 2000
insert @T select 7, 3, 4, 3000


select *
from @T t
where (select count(1) from @t where a=t.a and b<t.b)=0



(所影响的行数为 1 行)


(所影响的行数为 1 行)


(所影响的行数为 1 行)


(所影响的行数为 1 行)


(所影响的行数为 1 行)


(所影响的行数为 1 行)


(所影响的行数为 1 行)

id A B C
----------- ----------- ----------- -----------
1 1 1 10
3 2 1 100
5 3 2 1000

(所影响的行数为 3 行)

回复
dawugui 2007-12-24
create table tb(id int,  A int,  B int,  C int)
insert into tb values(1, 1, 1, 10 )
insert into tb values(2, 1, 2, 20 )
insert into tb values(3, 2, 1, 100 )
insert into tb values(4, 2, 2, 200 )
insert into tb values(5, 3, 2, 1000 )
insert into tb values(6, 3, 3, 2000 )
insert into tb values(7, 3, 4, 3000 )
go

--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 b = (select min(b) from tb where a = a.a) order by a.a
--方法2:
select a.* from tb a where not exists(select 1 from tb where a = a.a and b < a.b) order by a.a
--方法3:
select a.* from tb a,(select a,min(b) b from tb group by a) b where a.a = b.a and a.b = b.b order by a.a
--方法4:
select a.* from tb a inner join (select a , min(b) b from tb group by a) b on a.a = b.a and a.b = b.b order by a.a
--方法5
select a.* from tb a where 1 > (select count(*) from tb where a = a.a and b < a.b) order by a.a

drop table tb

/*
id A B C
----------- ----------- ----------- -----------
1 1 1 10
3 2 1 100
5 3 2 1000

(3 行受影响)

id A B C
----------- ----------- ----------- -----------
1 1 1 10
3 2 1 100
5 3 2 1000

(3 行受影响)

id A B C
----------- ----------- ----------- -----------
1 1 1 10
3 2 1 100
5 3 2 1000

(3 行受影响)

id A B C
----------- ----------- ----------- -----------
1 1 1 10
3 2 1 100
5 3 2 1000

(3 行受影响)

id A B C
----------- ----------- ----------- -----------
1 1 1 10
3 2 1 100
5 3 2 1000

(3 行受影响)

*/
回复
中国风 2007-12-24
declare @T table(id int,   A int,   B int,  C int)
insert @T select 1, 1, 1, 10
insert @T select 2, 1, 2, 20
insert @T select 3, 2, 1, 100
insert @T select 4, 2, 2, 200
insert @T select 5, 3, 2, 1000
insert @T select 6, 3, 3, 2000
insert @T select 7, 3, 4, 3000


select * from @T t where not exists(select 1 from @t where a=t.a and b<t.b)



(所影响的行数为 1 行)

id A B C
----------- ----------- ----------- -----------
1 1 1 10
3 2 1 100
5 3 2 1000

(所影响的行数为 3 行)

回复
dawugui 2007-12-24
create table tb(id int,  A int,  B int,  C int)
insert into tb values(1, 1, 1, 10 )
insert into tb values(2, 1, 2, 20 )
insert into tb values(3, 2, 1, 100 )
insert into tb values(4, 2, 2, 200 )
insert into tb values(5, 3, 2, 1000 )
insert into tb values(6, 3, 3, 2000 )
insert into tb values(7, 3, 4, 3000 )
go

select t.* from tb t where b = (select min(b) from tb where a = t.a) order by a

drop table tb

/*
id A B C
----------- ----------- ----------- -----------
1 1 1 10
3 2 1 100
5 3 2 1000

(3 行受影响)
*/
回复
中国风 2007-12-24
看看先..
回复
WAWQ 2007-12-24
感谢大家的帮助!!!

楼上的运行结果好像不大对阿~~

还没弄明白,期待中 。 。 。
回复
liangCK 2007-12-24
select * from tb a where not exists(select 1 from tb where a.A=A and a.B <B)
回复
liangCK 2007-12-24
select * from tb a where not exists(select 1 from tb where a.A=A and a.C<C)
回复
dawugui 2007-12-24
--按某一字段分组取最大(小)值所在行的数据
(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')
go

select * , px = identity(int,1,1) into tmp from tb

select 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')
go

select 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)
*/
回复
dawugui 2007-12-24
select t.* from tb t where b = (select min(b) from tb where a = b.a)
回复
发动态
发帖子
MS-SQL Server
创建于2007-09-28

3.2w+

社区成员

MS-SQL Server相关内容讨论专区
申请成为版主
社区公告
暂无公告