MEDIAN Function
Computes the 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
pivottransform, the function is computed for each instance of the value specified in thegroupparameter. See Pivot Transform.
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
median(myRating)
Output: Returns the median of the values in the myRating column.
Syntax and Arguments
median(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 |
For more information on the group and limit parameters, see Pivot Transform.
For more information on syntax standards, see Language Documentation Syntax Notes.
function_col_ref
Name of the column the values of which you want to calculate the median. Column must contain Integer or Decimal values.
Literal values are not supported as inputs.
Multiple columns and wildcards are not supported.
Usage Notes:
Required? | Data Type | Example Value |
|---|---|---|
Yes | String (column reference) | myValues |
Examples
ヒント
For additional examples, see Common Tasks.
Example - Percentile functions
This example illustrates you to apply percentile functions.
Functions:
Item | Description |
|---|---|
MEDIAN Function | Computes the median from all row values in a column or group. Input column can be of Integer or Decimal. |
PERCENTILE Function | Computes a specified percentile across all row values in a column or group. Input column can be of Integer or Decimal. |
QUARTILE Function | Computes a specified quartile across all row values in a column or group. Input column can be of Integer or Decimal. |
APPROXIMATEMEDIAN Function | Computes the approximate median from all row values in a column or group. Input column can be of Integer or Decimal. |
APPROXIMATEPERCENTILE Function | Computes an approximation for a specified percentile across all row values in a column or group. Input column can be of Integer or Decimal. |
APPROXIMATEQUARTILE Function | Computes an approximation for a specified quartile across all row values in a column or group. Input column can be of Integer or Decimal. |
Source:
The following table lists each student's height in inches:
Student | Height |
|---|---|
1 | 64 |
2 | 65 |
3 | 63 |
4 | 64 |
5 | 62 |
6 | 66 |
7 | 66 |
8 | 65 |
9 | 69 |
10 | 66 |
11 | 73 |
12 | 69 |
13 | 69 |
14 | 61 |
15 | 64 |
16 | 61 |
17 | 71 |
18 | 67 |
19 | 73 |
20 | 66 |
Transformation:
Use the following transformations to calculate the median height in inches, a specified percentile and the first quartile.
The first function uses a precise algorithm which can be slow to execute across large datasets.
The second function uses an appropriate approximation algorithm, which is much faster to execute across large datasets.
These approximate functions can use an error boundary parameter, which is set to
0.4(0.4%) across all functions.
Median: This transformation calculates the median value, which corresponds to the 50th percentile.
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | median(heightIn) |
Parameter: New column name | 'medianIn' |
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | approximatemedian(heightIn, 0.4) |
Parameter: New column name | 'approxMedianIn' |
Percentile: This transformation calculates the 68th percentile.
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | percentile(heightIn, 68, linear) |
Parameter: New column name | 'percentile68In' |
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | approximatepercentile(heightIn, 68, 0.4) |
Parameter: New column name | 'approxPercentile68In' |
Quartile: This transformation calculates the first quartile, which corresponds to the 25th percentile.
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | quartile(heightIn, 1, linear) |
Parameter: New column name | 'percentile25In' |
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | approximatequartile(heightIn, 1, 0.4) |
Parameter: New column name | 'approxPercentile25In' |
Results:
studentId | heightIn | approxPercentile25In | percentile25In | approxPercentile68In | percentile68In | approxMedianIn | medianIn |
|---|---|---|---|---|---|---|---|
1 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
2 | 65 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
3 | 63 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
4 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
5 | 62 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
6 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
7 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
8 | 65 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
9 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
10 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
11 | 73 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
12 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
13 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
14 | 61 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
15 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
16 | 61 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
17 | 71 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
18 | 67 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
19 | 73 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
20 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |