求一条SQL语句

[rottenapple]

目前的结果集如下：
id name flag
1 Common 1
1 Common 1
3 Fund 0
3 Fund 1
2 Broker 1
2 Broker 0

想要实现的结果如下：
1 Common 1
3 Fund 1
2 Broker 1
也就是说，重复的记录取Flag最大的一条记录。
能否用SQL语句实现？不用游标。

[rottenapple]

select [id],[name],max(flag) from tb group by id,name
是可以，但是如果我还想把结果排序的话，能不能只select一次就搞定。现在的办法是
select * from (
select [id],[name],max(flag) from tb group by id,name)
order by id

[pt1314917]

如果除了flag不同，就可以用这个
select   id,name,max(flag)   
from   table 
group   by   id,name

如果id也不相同
select * from table a where flag in(select max(flag) from table name=a.name)
或者：
select * from table a where not exists(select 1 from table where name=a.name and flag<a.flag)

[renzhe02]

排序
select id,name,max(flag)
from table
group by id,name
order by id,name

[dawugui]

--按某一字段分组取最大(小)值所在行的数据(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
*/

[kk19840210]

select id,name,flag=max(flag) from tablename group by id,name

[dawugui]

select * from tb t where flag = (select flag from tb where id = t.id and name = t.name)

[dawugui]

[code=SQL]select * from tb t where flag = (select max(flag) from tb where id = t.id and name = t.name)

[/code]

[dawugui]

select * from tb t where flag exists (select flag from tb where id = t.id and name = t.name)

[fa_ge]

create table #t
(id1 int identity(1,1),id   int,          name    varchar(10),     flag int )
insert into #t
select 1, 'Common', 1   union all
select 1, 'Common' ,1   union all 
select 3, 'Fund' ,0     union all
select 3, 'Fund' ,1     union all
select 2, 'Broker', 1   union all
select 2, 'Broker', 0 

select id,name,flag from #t a
where (select count(1) from #t where a.id=id and id1<=a.id1)<2

/*
id          name       flag        
----------- ---------- ----------- 
1           Common     1
3           Fund       0
2           Broker     1

*/

[fa_ge]

借一个自动编号id,很好解决的

[gggg007]

select [id],[name],max(flag) from tb group by id,name

[backhead]

select `id`,name,max(flag) from table order by id,name

[-狙击手-]

create table #t
(id   int,          name    varchar(10),     flag int )
insert into #t
select 1, 'Common', 1   union all
select 1, 'Common' ,1   union all 
select 3, 'Fund' ,0     union all
select 3, 'Fund' ,1     union all
select 2, 'Broker', 1   union all
select 2, 'Broker', 0 

select distinct id,name,flag 
from #t a
where not exists(select * from #t where a.id = id and a.name = name and flag < a.flag)


drop table #t

/*

id          name       flag        
----------- ---------- ----------- 
1           Common     1
2           Broker     0
3           Fund       0

（所影响的行数为 3 行）
*/

[-狙击手-]

或者是这样


select id,name,max(flag)
from table
group by id,name