DENSERANK Function
Computes the rank of an ordered set of value within groups. Tie values are assigned the same rank, and the next ranking is incremented by 1.
Rank values start at
1and increment.Ranking order varies depending on the data type of the source data.
You must use the
groupandorderparameters to define the groups of records and the order of those records to which this function is applied.This function works with the following transforms:
This function assigns ranking of the next value of a set of ties as a single increment more. For more discrete ranking, see RANK Function.
Wrangle vs. SQL: This function is part of Wrangle, a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.
Basic Usage
denserank() order:Times group:Racer
Output: Returns the dense ranking of Times values, grouped by the Racer column.
Syntax and Arguments
denserank() order: order_col group: group_col
For more information on the orderand groupparameters, see Window Transform.
For more information on syntax standards, see Language Documentation Syntax Notes.
Examples
Astuce
For additional examples, see Common Tasks.
Example - Rank Functions
This example demonstrates you to generate a ranked order of values.
Functions:
Item | Description |
|---|---|
RANK Function | Computes the rank of an ordered set of value within groups. Tie values are assigned the same rank, and the next ranking is incremented by the number of tie values. |
DENSERANK Function | Computes the rank of an ordered set of value within groups. Tie values are assigned the same rank, and the next ranking is incremented by 1. |
Source:
The following dataset contains lap times for three racers in a four-lap race. Note that for some racers, there are tie values for lap times.
Runner | Lap | Time |
|---|---|---|
Dave | 1 | 72.2 |
Dave | 2 | 73.31 |
Dave | 3 | 72.2 |
Dave | 4 | 70.85 |
Mark | 1 | 71.73 |
Mark | 2 | 71.73 |
Mark | 3 | 72.99 |
Mark | 4 | 70.63 |
Tom | 1 | 74.43 |
Tom | 2 | 70.71 |
Tom | 3 | 71.02 |
Tom | 4 | 72.98 |
Transformation:
You can apply the RANK() function to the Time column, grouped by individual runner:
Transformation Name | |
|---|---|
Parameter: Formulas | RANK() |
Parameter: Group by | Runner |
Parameter: Order by | Time |
You can use the DENSERANK() function on the same column, grouping by runner:
Transformation Name | |
|---|---|
Parameter: Formulas | DENSERANK() |
Parameter: Group by | Runner |
Parameter: Order by | Time |
Results:
After renaming the columns, you have the following output:
Runner | Lap | Time | Rank | Rank-Dense |
|---|---|---|---|---|
Mark | 4 | 70.63 | 1 | 1 |
Mark | 1 | 71.73 | 2 | 2 |
Mark | 2 | 71.73 | 2 | 2 |
Mark | 3 | 72.99 | 4 | 3 |
Tom | 2 | 70.71 | 1 | 1 |
Tom | 3 | 71.02 | 2 | 2 |
Tom | 4 | 72.98 | 3 | 3 |
Tom | 1 | 74.43 | 4 | 4 |
Dave | 4 | 70.85 | 1 | 1 |
Dave | 1 | 72.2 | 2 | 2 |
Dave | 3 | 72.2 | 2 | 2 |
Dave | 2 | 73.31 | 4 | 3 |