SQLServer2005 中的几个统计技巧

在SQLServer中我们可以用over子句中来代替子查询实现来提高效率,over子句除了排名函数之外也可以和聚合函数配合。实现代码如下：

 

use tempdb 
go 
if (object_id ('tb' ) is not null ) 
drop table tb 
go 
create table tb (name varchar (10 ), val int ) 
go 
insert into tb 
select 'aa' , 10 
union all select 'aa' , 20 
union all select 'aa' , 20 
union all select 'aa' , 30 
union all select 'bb' , 55 
union all select 'bb' , 45 
union all select 'bb' , 0 

select * 
, 排名 = rank ()over (partition by name order by val ) 
, 占比 = cast (val * 1.0 / sum (val )over (partition by name ) as decimal (2 , 2 )) 
, 距最大 = val - max (val )over (partition by name ) 
, 距最小 = val - min (val )over (partition by name ) 
, 距平均 = val - avg (val )over (partition by name ) 
from tb