APPROXIMATEPERCENTILE Function

D toc

Excerpt
Computes an approximation for a specified percentile across all row values in a column or group. Input column can be of Integer or Decimal.

If a row contains a missing or null value, it is not factored into the calculation. If the entire column contains no values, the function returns a null value.
When used in a pivot transform, the function is computed for each instance of the value specified in the group parameter. See Pivot Transform.
The approximate percentile functions utilize a different algorithm for efficiently estimating quantiles for streaming and distributed processing, depending on the running environment where the function is computed.
Tip
Tip: Approximation functions are suitable for larger datasets. As the number of rows increases, accuracy and calculation performance improves for these functions.
- For an exact calculation of this function, see PERCENTILE Function.

D s lang vs sql

D s

snippet	Basic

D lang syntax

RawWrangle	true
Type	ref
showNote	true
WrangleText	pivot value:approximatepercentile(myScores, 25) group:postal_code limit:1

approximatepercentile(myScores, 25)

Output: Computes the approximate value that is at the 25th percentile across all values in the myScores column.

D s

snippet	Syntax

D lang syntax

RawWrangle	true
Type	syntax
showNote	true
WrangleText	pivot value:approximatepercentile(function_col_ref,num_percentile) [group:group_col_ref] [limit:limit_count]

approximatepercentile(function_col_ref,num_percentile) [group:group_col_ref] [limit:limit_count]

Argument	Required?	Data Type	Description
function_col_ref	Y	string	Name of column to which to apply the function
num_percentile	Y	integer	Integer value between 1-100 of the percentile to compute
dec_error_bound	N	decimal	Error factor for computing approximations. Decimal value represents error factor as a percentage (`0.4` is 0.4%).

For more information on the group and limit parameters, see Pivot Transform.

D s lang notes

function_col_ref

Name of the column the values of which you want to calculate the percentile. Column must contain Integer or Decimal values.

Literal values are not supported as inputs.
Multiple columns and wildcards are not supported.

D s

snippet	usage

Required?	Data Type	Example Value
Yes	String (column reference)	`precipitationIn`

num_percentile

Integer literal value indicating the percentile that you wish to compute. Input value must be between 1 and 100, inclusive.

Column or function references are not supported.
Multiple columns and wildcards are not supported.

D s

snippet	usage

Required?	Data Type	Example Value
Yes	Integer	`55`

dec_error_bound

As needed, you can insert an error boundary factor as a parameter into the computation of this approximate value.

This value must be a Decimal literal value.
This decimal value represents the percentage error factor. By default, this value is 0.5 (0.5%).

D s

snippet	usage

Required?	Data Type	Example Value
No	Decimal (literal)	`0.01`

D s

snippet	Examples

Example - Percentile functions

Include Page

	EXAMPLE - Percentile Functions
	EXAMPLE - Percentile Functions

D s also

label	aggregate

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Key

function_col_ref

num_percentile

dec_error_bound

Example - Percentile functions