Oracle ROW_NUMBER() OVER()函數用法詳解 （分組排序 例子多）

轉載☞：https://blog.csdn.net/qq_25221835/article/details/82762416

ROW_NUMBER

語法

語法格式：row_number() over(partition by 分組列 order by 排序列 desc)

解釋

row_number() over()分組排序功能：

在使用 row_number() over()函數時候，over()里頭的分組以及排序的執行晚於 where 、group by、  order by 的執行。

示例1

表數據：

create table TEST_ROW_NUMBER_OVER(
       id varchar(10) not null,
       name varchar(10) null,
       age varchar(10) null,
       salary int null
);
select * from TEST_ROW_NUMBER_OVER t;
 
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(1,'a',10,8000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(1,'a2',11,6500);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(2,'b',12,13000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(2,'b2',13,4500);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(3,'c',14,3000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(3,'c2',15,20000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(4,'d',16,30000);
insert into TEST_ROW_NUMBER_OVER(id,name,age,salary) values(5,'d2',17,1800);

依次排序：對查詢結果進行排序（無分組）

select id,name,age,salary,row_number()over(order by salary desc) rn
from TEST_ROW_NUMBER_OVER t

結果

 

 

根據id分組排序

select id,name,age,salary,row_number()over(partition by id order by salary desc) rank
from TEST_ROW_NUMBER_OVER t

結果

 

找出每一組中序號為一的數據

select * from(select id,name,age,salary,row_number()over(partition by id order by salary desc) rank
from TEST_ROW_NUMBER_OVER t)
where rank <2

結果

 

排序找出年齡在13歲到16歲數據，按salary排序

select id,name,age,salary,row_number()over(order by salary desc)  rank
from TEST_ROW_NUMBER_OVER t where age between '13' and '16'

結果：結果中 rank 的序號，其實就表明了 over(order by salary desc) 是在where age between and 后執行的

 

示例二

使用row_number（）函數進行編號

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

在訂單中按價格的升序進行排序，並給每條記錄進行排序代碼如下：

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

統計出每一個各戶的所有訂單並按每一個客戶下的訂單的金額 升序排序，同時給每一個客戶的訂單進行編號。這樣就知道每個客戶下幾單了

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

統計每一個客戶最近下的訂單是第幾次下的訂單

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 '下單次數',customerID from tabs 
group by customerID 

篩選出客戶第一次下的訂單

思路。利用rows=1來查詢客戶第一次下的訂單記錄

    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 

注意：在使用over等開窗函數時，over里頭的分組及排序的執行晚於“where，group by，order by”的執行。

    select   
    ROW_NUMBER() over(partition by customerID  order by insDT) as rows,  
    customerID,totalPrice, DID  
    from OP_Order where insDT>'2011-07-22'