oracle为相同行记录增加序号列(row_number()函数)

[sql]代码库

表结构及测试数据如下:
Sql代码  
CREATE TABLE t_row_str(  
ID INT,  
col VARCHAR2(10));  
INSERT INTO t_row_str VALUES(1,'a');  
INSERT INTO t_row_str VALUES(1,'b');  
INSERT INTO t_row_str VALUES(1,'c');  
INSERT INTO t_row_str VALUES(2,'a');  
INSERT INTO t_row_str VALUES(2,'d');  
INSERT INTO t_row_str VALUES(2,'e');  
INSERT INTO t_row_str VALUES(3,'c');  
COMMIT;  
SELECT * FROM t_row_str;  
 
测试数据输出结果:
 
结果集代码  
ID COL  
-- ----------  
 1 a  
 1 b  
 1 c  
 2 a  
 2 d  
 2 e  
 3 c  
 
 
执行如下SQL语句获得想要的结果:
Sql代码  
SELECT id, col, row_number() over(PARTITION BY id ORDER BY col) AS rn  
  FROM t_row_str  
 
输出结果:
结果集代码  
ID COL                RN  
-- ---------- ----------  
 1 a                   1  
 1 b                   2  
 1 c                   3  
 2 a                   1  
 2 d                   2  
 2 e                   3  
 3 c                   1