Purpose
The NTILE function is an analytic function that divides an ordered dataset into several groups and assigns an appropriate group number to each row. The group number ranges from 1 to expr.
Syntax
NTILE (expr) OVER ([ query_partition_clause ] order_by_clause)
Parameters
Parameter |
Description |
|---|---|
| expr | Specifies the number of groups to divide the data into.
NTILE, within other analytic functions. However, you can use other built-in functions or expressions in expr. |
| OVER | Defines the window for calculation using the OVER clause. For more information, see Analytic Function Description. |
Return type
The function returns data of the NUMERIC type.
Examples
Assume that the emp_msg table has been created. Query the emp_msg table to divide the employees into 5 levels based on the sal column.
obclient> SELECT * FROM emp_msg;
+--------+--------+------+------+
| DEPTNO | ENAME | SAL | MGR |
+--------+--------+------+------+
| 10 | CLARK | 2750 | 7839 |
| 10 | KING | 5300 | NULL |
| 10 | MILLER | 1600 | 7782 |
| 20 | ADAMS | 1400 | 7788 |
| 20 | FORD | 3300 | 7566 |
| 20 | JONES | 3275 | 7839 |
| 20 | SCOTT | 3300 | 7566 |
| 20 | SMITH | 1100 | 7902 |
| 30 | ALLEN | 1900 | 7698 |
| 30 | BLAKE | 3150 | 7839 |
| 30 | JAMES | 1250 | 7698 |
| 30 | MARTIN | 1550 | 7698 |
| 30 | TURNER | 1800 | 7698 |
| 30 | WARD | 1550 | 7698 |
| 30 | SCLARK | 1750 | 7839 |
+--------+--------+------+------+
15 rows in set
obclient> SELECT ename,sal,NTILE(5) OVER (ORDER BY sal DESC) sal_ntile FROM emp_msg ORDER BY sal DESC;
+--------+------+-----------+
| ENAME | SAL | SAL_NTILE |
+--------+------+-----------+
| KING | 5300 | 1 |
| FORD | 3300 | 1 |
| SCOTT | 3300 | 1 |
| JONES | 3275 | 2 |
| BLAKE | 3150 | 2 |
| CLARK | 2750 | 2 |
| ALLEN | 1900 | 3 |
| TURNER | 1800 | 3 |
| SCLARK | 1750 | 3 |
| MILLER | 1600 | 4 |
| MARTIN | 1550 | 4 |
| WARD | 1550 | 4 |
| ADAMS | 1400 | 5 |
| JAMES | 1250 | 5 |
| SMITH | 1100 | 5 |
+--------+------+-----------+
15 rows in set