sqlserver巧用row_number和partition by分组取top数据

--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  
 
语法形式:ROW_NUMBER() OVER(PARTITION BY COL1 ORDER BY COL2) 
解释:根据COL1分组,在分组内部根据 COL2排序,而此函数计算的值就表示每组内部排序后的顺序编号(组内连续的唯一的)
 
sqlserver巧用row_number和partition by分组取top数据
结果:
sqlserver巧用row_number和partition by分组取top数据
 
 
 
--------------------------->>>

sqlserver巧用row_number和partition by分组取top数据,布布扣,bubuko.com

sqlserver巧用row_number和partition by分组取top数据

上一篇:FSharp 调用 Oracle.ManagedDataAccess.dll


下一篇:OpenTSDB部署和使用