计算行号。从1开始递增。
使用限制
窗口函数的使用限制如下:
窗口函数只能出现在
select
语句中。窗口函数中不能嵌套使用窗口函数和聚合函数。
窗口函数不能和同级别的聚合函数一起使用。
命令格式
row_number() over([partition_clause] [orderby_clause])
命令说明
计算当前行在分区中的行号,从1开始递增。
参数说明
请参见windowing_definition。不允许包含frame_clause。
返回值说明
返回BIGINT类型。
示例数据
为便于理解各函数的使用方法,本文为您提供源数据,基于源数据提供函数相关示例。创建表emp,并添加数据,命令示例如下:
create table if not exists emp
(empno bigint,
ename string,
job string,
mgr bigint,
hiredate datetime,
sal bigint,
comm bigint,
deptno bigint);
tunnel upload emp.txt emp;
emp.txt中的数据如下:
7369,SMITH,CLERK,7902,1980-12-17 00:00:00,800,,20
7499,ALLEN,SALESMAN,7698,1981-02-20 00:00:00,1600,300,30
7521,WARD,SALESMAN,7698,1981-02-22 00:00:00,1250,500,30
7566,JONES,MANAGER,7839,1981-04-02 00:00:00,2975,,20
7654,MARTIN,SALESMAN,7698,1981-09-28 00:00:00,1250,1400,30
7698,BLAKE,MANAGER,7839,1981-05-01 00:00:00,2850,,30
7782,CLARK,MANAGER,7839,1981-06-09 00:00:00,2450,,10
7788,SCOTT,ANALYST,7566,1987-04-19 00:00:00,3000,,20
7839,KING,PRESIDENT,,1981-11-17 00:00:00,5000,,10
7844,TURNER,SALESMAN,7698,1981-09-08 00:00:00,1500,0,30
7876,ADAMS,CLERK,7788,1987-05-23 00:00:00,1100,,20
7900,JAMES,CLERK,7698,1981-12-03 00:00:00,950,,30
7902,FORD,ANALYST,7566,1981-12-03 00:00:00,3000,,20
7934,MILLER,CLERK,7782,1982-01-23 00:00:00,1300,,10
7948,JACCKA,CLERK,7782,1981-04-12 00:00:00,5000,,10
7956,WELAN,CLERK,7649,1982-07-20 00:00:00,2450,,10
7956,TEBAGE,CLERK,7748,1982-12-30 00:00:00,1300,,10
示例
将所有职工根据部门(deptno)分组(作为开窗列),每个组内根据薪水(sal)做降序排序,获得职工在自己组内的序号。命令示例如下:
select deptno, ename, sal, row_number() over (partition by deptno order by sal desc) as nums from emp;
返回结果如下:
+------------+------------+------------+------------+
| deptno | ename | sal | nums |
+------------+------------+------------+------------+
| 10 | JACCKA | 5000 | 1 |
| 10 | KING | 5000 | 2 |
| 10 | CLARK | 2450 | 3 |
| 10 | WELAN | 2450 | 4 |
| 10 | TEBAGE | 1300 | 5 |
| 10 | MILLER | 1300 | 6 |
| 20 | SCOTT | 3000 | 1 |
| 20 | FORD | 3000 | 2 |
| 20 | JONES | 2975 | 3 |
| 20 | ADAMS | 1100 | 4 |
| 20 | SMITH | 800 | 5 |
| 30 | BLAKE | 2850 | 1 |
| 30 | ALLEN | 1600 | 2 |
| 30 | TURNER | 1500 | 3 |
| 30 | MARTIN | 1250 | 4 |
| 30 | WARD | 1250 | 5 |
| 30 | JAMES | 950 | 6 |
+------------+------------+------------+------------+
相关函数
ROW_NUMBER函数属于窗口函数,更多对指定开窗列的数据进行求和、数值排序的相关函数请参见窗口函数。
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