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D toc

Excerpt

Computes an approximation for a specified quartile 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.

Quartiles are computed as follows:

QuartileDescription
0Minimum value
125th percentile
2Median value
375th percentile and higher

D s lang vs sql

D s
snippet Basic

D lang syntax
RawWrangle true ref true pivot value:approximatequartile(myScores, 25) group:postal_code limit:1

approximatequartile(myScores, 3)

Output: Computes the approximate value that is at the 3rd quartile across all values in the myScores column.

D s
snippet Syntax

D lang syntax
RawWrangle true syntax true pivot value:approximatequartile) [group:group_col_ref] [limit:limit_count]

approximatequartile(function_col_ref,num_quartile) [group:group_col_ref] [limit:limit_count]

ArgumentRequired?Data TypeDescription
function_col_refYstringName of column to which to apply the function
num_quartileYintegerInteger value (0-3) of the quartile to compute
dec_error_boundNdecimalError 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 quartile. 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 TypeExample Value
YesString (column reference)`precipitationIn `

### num_quartile

Integer literal value indicating the quartile that you wish to compute. Input value must be between `0` and `3`, inclusive.

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

D s
snippet usage

Required?Data TypeExample Value
YesInteger3

### 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 TypeExample Value
NoDecimal (literal)`0.01 `

D s
snippet Examples

### Example - Percentile functions

Include Page
 EXAMPLE - Percentile Functions EXAMPLE - Percentile Functions

D s also
label aggregate