sqlserver巧用row_number和partition by分组取top数据

浏览数：33 / 时间：2015年06月12日

From : http://www.jb51.net/article/29162.htm

--1.创建测试表 
create table #score 
( 
name varchar(20), 
subject varchar(20), 
score int 
) 
--2.插入测试数据 
insert into #score(name,subject,score) values(‘张三‘,‘语文‘,98) 
insert into #score(name,subject,score) values(‘张三‘,‘数学‘,80) 
insert into #score(name,subject,score) values(‘张三‘,‘英语‘,90) 
insert into #score(name,subject,score) values(‘李四‘,‘语文‘,88) 
insert into #score(name,subject,score) values(‘李四‘,‘数学‘,86) 
insert into #score(name,subject,score) values(‘李四‘,‘英语‘,88) 
insert into #score(name,subject,score) values(‘李明‘,‘语文‘,60) 
insert into #score(name,subject,score) values(‘李明‘,‘数学‘,86) 
insert into #score(name,subject,score) values(‘李明‘,‘英语‘,88) 
insert into #score(name,subject,score) values(‘林风‘,‘语文‘,74) 
insert into #score(name,subject,score) values(‘林风‘,‘数学‘,99) 
insert into #score(name,subject,score) values(‘林风‘,‘英语‘,59) 
insert into #score(name,subject,score) values(‘严明‘,‘英语‘,96) 
--3.取每个学科的前3名数据 
select * from 
( 
select subject,name,score,ROW_NUMBER() over(PARTITION by subject order by score desc) as num from #score 
) T where T.num <= 3 order by subject 
--4.删除临时表 
truncate table #score  
drop table #score