sql ROW_NUMBER() 排序函数

浏览数：31 / 时间：2015年06月12日

1使用row_number（）函数进行编号：如

1	`select` `email,customerID, ROW_NUMBER() over(order` `by` `psd)` `as` `rows` `from` `QT_Customer`

原理：先按psd进行排序，排序完后，给每条数据进行编号。

2.在订单中按价格的升序进行排序，并给每条记录进行排序

代码如下：

select DID,customerID,totalPrice,ROW_NUMBER() over(order by totalPrice) as rows from OP_Order

3.统计出每一个各户的所有订单并按每一个客户下的订单的金额升序排序，同时给每一个客户的订单进行编号。这样就知道每个客户下几单了。

如图：

代码如下：

select ROW_NUMBER() over(partition by customerID order by totalPrice) as rows,customerID,totalPrice, DID from OP_Order

1 select ROW_NUMBER() over(partition by customerID order by totalPrice) as rows,customerID,totalPrice, DID from OP_Order

4.统计每一个客户最近下的订单是第几次下的订单。

代码如下：

with tabs as
(
select ROW_NUMBER() over(partition by customerID order by totalPrice) as rows,customerID,totalPrice, DID from OP_Order
)

select MAX(rows) as ‘下单次数‘,customerID from tabs group by customerID

1 with tabs as
2 (
3 select ROW_NUMBER() over(partition by customerID order by totalPrice) as rows,customerID,totalPrice, DID from OP_Order
4 )
5
6 select MAX(rows) as ‘下单次数‘,customerID from tabs group by customerID

5.统计每一个客户所有的订单中购买的金额最小，而且并统计改订单中，客户是第几次购买的。

如图：

上图：rows表示客户是第几次购买。

思路：利用临时表来执行这一操作

1.先按客户进行分组，然后按客户的下单的时间进行排序，并进行编号。

2.然后利用子查询查找出每一个客户购买时的最小价格。

3.根据查找出每一个客户的最小价格来查找相应的记录。

代码如下：

with tabs as
(
　　select ROW_NUMBER() over(partition by customerID  order by insDT) as rows,customerID,totalPrice, DID from OP_Order
)
select * from tabs
where totalPrice in
   `(
            select MIN(totalPrice)from tabs group by customerID
　　)

1 with tabs as
2 (
3 select ROW_NUMBER() over(partition by customerID  order by insDT) as rows,customerID,totalPrice, DID from OP_Order
4 )
5 select * from tabs
6  where totalPrice in
7            (
8            select MIN(totalPrice)from tabs group by customerID
9            )

5.筛选出客户第一次下的订单。

思路。利用rows=1来查询客户第一次下的订单记录。

代码如下:

with tabs as
(
select ROW_NUMBER() over(partition by customerID order by insDT) as rows,* from OP_Order
)
select * from tabs where rows = 1

select * from OP_Order

1 with tabs as
2 (
3 select ROW_NUMBER() over(partition by customerID order by insDT) as rows,* from OP_Order
4 )
5 select * from tabs where rows = 1
6
7 select * from OP_Order

6.rows_number()可用于分页

思路：先把所有的产品筛选出来，然后对这些产品进行编号。然后在where子句中进行过滤。

7.注意：在使用over等开窗函数时，over里头的分组及排序的执行晚于“where，group by，order by”的执行。

如下代码：

1  select
2  ROW_NUMBER() over(partition by customerID  order by insDT) as rows,
3  customerID,totalPrice, DID
4   from OP_Order where insDT>‘2011-07-22‘