ROW_NUMBER - MaxCompute - Alibaba Cloud Documentation Center

Calculates the sequence number of a row. The row number starts from 1.

Limits

Before you use window functions, take note of the following limits:

Window functions are supported only in SELECT statements.
A window function cannot contain nested window functions or nested aggregate functions.
You cannot use window functions together with aggregate functions of the same level.

Syntax

row_number() over([partition_clause] [orderby_clause])

Description

Returns the sequence number of the current row in a partition. The sequence number counts from 1.

Parameters

For more information, see windowing_definition. frame_clause is not supported.

Return value

A value of the BIGINT type is returned.

Sample data

This section provides sample source data and examples for you to understand how to use the functions. Create a table named emp and insert the sample data into the table. Sample statement:

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;

The emp.txt file contains the following sample data:

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

Examples

Group all employees based on the deptno column. In each group, sort the employees in descending order based on the sal value, and obtain the sequence numbers of the employees in their respective groups. Sample statement:

select deptno, ename, sal, row_number() over (partition by deptno order by sal desc) as nums from emp;

The following result is returned:

+------------+------------+------------+------------+
| 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          |
+------------+------------+------------+------------+

Related functions

ROW_NUMBER is a window function. For more information about the functions that are used to calculate the sum of data of columns in a window and to sort data, see Window functions.