Aggregate Syntax
percent_rank_aggregate::=
Analytic Syntax
percent_rank_analytic::=
See Also:
"Analytic Functions" for information on syntax, semantics, and restrictions
Purpose
PERCENT_RANK
is similar to the CUME_DIST
(cumulative distribution) function. The range of values returned by PERCENT_RANK
is 0 to 1, inclusive. The first row in any set has a PERCENT_RANK
of 0. The return value is NUMBER
.
See Also:
Table 2-8 for more information on implicit conversion
As an aggregate function, PERCENT_RANK
calculates, for a hypothetical row r
identified by the arguments of the function and a corresponding sort specification, the rank of row r
minus 1 divided by the number of rows in the aggregate group. This calculation is made as if the hypothetical row r
were inserted into the group of rows over which Oracle Database is to aggregate.
The arguments of the function identify a single hypothetical row within each aggregate group. Therefore, they must all evaluate to constant expressions within each aggregate group. The constant argument expressions and the expressions in the ORDER
BY
clause of the aggregate match by position. Therefore the number of arguments must be the same and their types must be compatible.
As an analytic function, for a row r
, PERCENT_RANK
calculates the rank of r
minus 1, divided by 1 less than the number of rows being evaluated (the entire query result set or a partition).
See Also:
Appendix C in Oracle Database Globalization Support Guide for the collation determination rules, which define the collation PERCENT_RANK
uses to compare character values for the ORDER
BY
clause
Aggregate Example
The following example calculates the percent rank of a hypothetical employee in the sample table hr.employees
with a salary of $15,500 and a commission of 5%:
SELECT PERCENT_RANK(15000, .05) WITHIN GROUP (ORDER BY salary, commission_pct) "Percent-Rank" FROM employees; Percent-Rank ------------ .971962617
Analytic Example
The following example calculates, for each employee, the percent rank of the employee's salary within the department:
SELECT department_id, last_name, salary, PERCENT_RANK() OVER (PARTITION BY department_id ORDER BY salary DESC) AS pr FROM employees ORDER BY pr, salary, last_name; DEPARTMENT_ID LAST_NAME SALARY PR ------------- ------------------------- ---------- ---------- 10 Whalen 4400 0 40 Mavris 6500 0 Grant 7000 0 . . . 80 Vishney 10500 .181818182 80 Zlotkey 10500 .181818182 30 Khoo 3100 .2 . . . 50 Markle 2200 .954545455 50 Philtanker 2200 .954545455 50 Olson 2100 1 . . .