SQL2005 学习笔记 窗口函数(OVER)

复制代码 代码如下:

--建立订单表
create table SalesOrder(
OrderID int, --订单id
OrderQty decimal(18,2) --数量
)
go
--插入数据
insert into SalesOrder
select 1,2.0
union all
select 1,1.0
union all
select 1,3.0
union all
select 2,6.0
union all
select 2,1.1
union all
select 3,8.0
union all
select 3,1.1
union all
select 3,7.0
go
--查询得如下结果
select * from SalesOrder
go
OrderID OrderQty
----------- ------------
1 2.00
1 1.00
1 3.00
2 6.00
2 1.10
3 8.00
3 1.10
3 7.00

复制代码 代码如下:

--利用窗口函数和聚合开窗函数,可以很快实现上述要求
select OrderID,OrderQty,
sum(OrderQty) over() as [汇总],
convert(decimal(18,4), OrderQty/sum(OrderQty) over() ) as [每单所占比例],
sum(OrderQty) over(PARTITION BY OrderID) as [分组汇总],
convert(decimal(18,4),OrderQty/sum(OrderQty) over(PARTITION BY OrderID)) as [每单在各组所占比例]
from SalesOrder
order by OrderID

复制代码 代码如下:

--sql2000
declare @sum decimal(18,2)
select @sum=sum(OrderQty)
from SalesOrder
--按OrderID，计算每组的总计，然后插入临时表
select OrderID,sum(OrderQty) as su
into #t
from SalesOrder
group by OrderID
--连接临时表，得到结果
select s.OrderID,s.OrderQty,
@sum as [汇总],
convert(decimal(18,4),s.OrderQty/@sum) as [每单所占比例],
t.su as [分组汇总],
convert(decimal(18,4),s.OrderQty/t.su) as [每单在各组所占比例]
from SalesOrder s join #t t
on t.OrderID=s.OrderID
order by s.OrderID
drop table #t
go

复制代码 代码如下:

--与排名开窗函数使用
select OrderID,OrderQty,
rank() over(PARTITION BY orderid order by OrderQty ) as [分组排名],
rank() over(order by OrderQty ) as [排名]
from SalesOrder
order by orderid asc
--查询得如下结果
OrderID OrderQty 分组排名 排名
1 2.00 2 4
1 3.00 3 5
1 1.00 1 1
2 1.10 1 2
2 6.00 2 6
3 7.00 2 7
3 8.00 3 8
3 1.10 1 2