分类查询最大值记录，每类只要一条(100分)
分类查询最大值记录，每类如果有多个最大值按ID取最前一条
表A
id     tpye     value
1         1             34
2         2             23
3         3             39
4         1             34
5         2             25
6         3             23
7         1             33
8         2             25
9         3             38
10       1             26
查询结果
1         1             34
5         2             25
3         3             39


------解决方案--------------------
select * from A t where id in (select top 1 id from A where type=t.type order by value desc,id)
------解决方案--------------------
select t.* from 表A t where not exists(select 1 from 表A where type=t.type and id <t.id) order by t.type

select t.* from 表A t where t.id=(select top 1 id from 表A where type=t.type order by id) order by t.type

select t.* from 表A t where t.id=(select min(id) from 表A where type=t.type) order by t.type


------解决方案--------------------
前面错了，呵呵
select * from a as b
where not exists (select * from a where b.type=type and value> b.value)

------解决方案--------------------
1.
select * from a as b where not exists(select 1 from a where type=b.type and value> b.value)

2.
select * from a as b where id=(select top 1 id from a where type=b.type order by value desc)
------解决方案--------------------
create table tab(id int,tpye int, value int)
insert tab

select 1,1,34
union
select 2,2,23
union
select 3,3,39
union
select 4,1,34
union
select 5,2,25
union
select 6,3,23
union
select 7,1,33
union
select 8,2,25
union
select 9,3,38
union
select 10,1,26

select t.*
from tab t
where not exists(select 1 from tab where tpye=t.tpye and id <t.id)
------解决方案--------------------
create table #(id int, tpye int, value int)
insert into # select 1 , 1 , 34
union all select 2 , 2 , 23
union all select 3 , 3 , 39
union all select 4 , 1 , 34
union all select 5 , 2 , 25
union all select 6 , 3 , 23
union all select 7 , 1 , 33
union all select 8 , 2 , 25
union all select 9 , 3 , 38
union all select 10 , 1 , 26

select id=min(id),tpye,value=max(value) from (select * from # as b where not exists (select * from # where b.tpye=tpye and value> b.value))t group by tpye


---
1 1 34
5 2 25
3 3 39
------解决方案--------------------