Returns a unique, sequential number for each row within a partition, starting at 1.
Limitations
-
Window functions are supported only in
SELECTstatements. -
A window function cannot contain nested window functions or nested aggregate functions.
-
Window functions and aggregate functions of the same level cannot be used together.
Syntax
row_number() over ([partition_clause] [orderby_clause])frame_clause is not supported.
Usage notes
ROW_NUMBER assigns each row a unique number. No two rows in the same partition share the same value, even when the ORDER BY column contains ties — unlike RANK and DENSE_RANK, which assign the same number to tied rows.
-
`PARTITION BY`: Divides rows into independent groups before numbering. For example, use
PARTITION BY deptnoto restart the count at 1 for each department. -
`ORDER BY`: Determines the sequence within each partition. For example, use
ORDER BY sal DESCto number employees from highest to lowest salary.
For the full window specification, see windowing_definition.
Return value
Returns a value of the BIGINT type.
Examples
The following examples use a table named emp. To create the table and load the sample data, run:
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 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,,10Rank employees by salary within each department
The following query partitions employees by department and assigns a rank within each partition in descending salary order.
select deptno, ename, sal,
row_number() over (partition by deptno order by sal desc) as nums
from emp;Result:
+------------+------------+------------+------------+
| 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 |
+------------+------------+------------+------------+In department 10, JACCKA and KING both earn 5000 but receive different row numbers (1 and 2). ROW_NUMBER always assigns unique values — unlike RANK, which would assign both employees rank 1.
What's next
ROW_NUMBER is a window function. For other window functions that sort or rank data, see Window functions.