APPROXIMATEMEDIAN Function

D toc

D excerpt
Computes the approximate median from 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 MEDIAN Function.

D s lang vs sql

D s

snippet	Basic

D lang syntax

RawWrangle	true
Type	ref
showNote	true
WrangleText	pivot value:approximatemedian(myRating) group:postal_code limit:1

approximatemedian(myRating)

Output: Returns the approximate median of the values in the myRating column.

D s

snippet	Syntax

D lang syntax

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

approximatemedian(function_col_ref) [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
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

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

D s

snippet	usage

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

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

Include Page

	EXAMPLE - Percentile Functions
	EXAMPLE - Percentile Functions

D s also

label	aggregate

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