PERCENT_RANK (Transact-SQL)
Calculates the relative rank of a row within a group of rows in SQL Server 2012. Use PERCENT_RANK to evaluate the relative standing of a value within a query result set or partition. PERCENT_RANK is similar to the CUME_DIST function.
Składnia
PERCENT_RANK( )
OVER ( [ partition_by_clause ] order_by_clause )
Arguments
- OVER ( [ partition_by_clause ] order_by_clause**)**
partition_by_clause divides the result set produced by the FROM clause into partitions to which the function is applied. If not specified, the function treats all rows of the query result set as a single group. order_by_clause determines the logical order in which the operation is performed. The order_by_clause is required. The <rows or range clause> of the OVER syntax cannot be specified in a PERCENT_RANK function. For more information, see OVER Clause (Transact-SQL).
Return Types
float(53)
General Remarks
The range of values returned by PERCENT_RANK is greater than 0 and less than or equal to 1. The first row in any set has a PERCENT_RANK of 0. NULL values are included by default and are treated as the lowest possible values.
Examples
The following example uses the CUME_DIST function to compute the salary percentile for each employee within a given department. The value returned by the CUME_DIST function represents the percent of employees that have a salary less than or equal to the current employee in the same department. The PERCENT_RANK function computes the rank of the employee's salary within a department as a percentage. The PARTITION BY clause is specified to partition the rows in the result set by department. The ORDER BY clause in the OVER clause orders the rows in each partition. The ORDER BY clause in the SELECT statement sorts the rows in the whole result set.
USE AdventureWorks2012;
GO
SELECT Department, LastName, Rate,
CUME_DIST () OVER (PARTITION BY Department ORDER BY Rate) AS CumeDist,
PERCENT_RANK() OVER (PARTITION BY Department ORDER BY Rate ) AS PctRank
FROM HumanResources.vEmployeeDepartmentHistory AS edh
INNER JOIN HumanResources.EmployeePayHistory AS e
ON e.BusinessEntityID = edh.BusinessEntityID
WHERE Department IN (N'Information Services',N'Document Control')
ORDER BY Department, Rate DESC;
Here is the result set.
Department LastName Rate CumeDist PctRank
---------------------- ---------------------- --------------------- ---------------------- ----------------------
Document Control Arifin 17.7885 1 1
Document Control Norred 16.8269 0.8 0.5
Document Control Kharatishvili 16.8269 0.8 0.5
Document Control Chai 10.25 0.4 0
Document Control Berge 10.25 0.4 0
Information Services Trenary 50.4808 1 1
Information Services Conroy 39.6635 0.9 0.888888888888889
Information Services Ajenstat 38.4615 0.8 0.666666666666667
Information Services Wilson 38.4615 0.8 0.666666666666667
Information Services Sharma 32.4519 0.6 0.444444444444444
Information Services Connelly 32.4519 0.6 0.444444444444444
Information Services Berg 27.4038 0.4 0
Information Services Meyyappan 27.4038 0.4 0
Information Services Bacon 27.4038 0.4 0
Information Services Bueno 27.4038 0.4 0
(15 row(s) affected)