Excerpt 

Computes the standard deviation across all column values of Integer or Decimal type. 
The
standard deviation of a set of values attempts to measure the spread in values around the mean and is used to measure confidence in statistical results. A standard deviation of zero means that all values are the same, and a small standard deviation means that the values are closely bunched together. A high value for standard deviation indicates that the numbers are spread out widely. Standard deviation is always a positive value.
Standard deviation comes in two flavors:
 Population standard deviation computes the variance from all possible values.
 Sample standard deviation computes from a subset or sample of all values.
 Since has access to all available values, the computation for population standard deviation is used across the entire dataset.
If a row contains a missing or null value, it is not factored into the calculation. If no numeric values are detected in the input column, the function returns 0
.
The square of standard deviation is variance. See VAR Function.
For a version of this function computed over a rolling window of rows, see ROLLINGSTDEV Function.
D code 

pivot value:STDEV(myRating) group: postal_code limit:1 
Output: Generates a twocolumn table containing the unique values from the postal_code
column and the standard deviation of the group of values from the myRating
column for the postal_code
value. The limit
parameter defines the maximum number of output columns.
D code 

pivot value:STDEV(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.
function_col_ref
Name of the column the values of which you want to calculate the variance. Column must contain Integer or Decimal values.
 Literal values are not supported as inputs.
 Multiple columns and wildcards are not supported.
Required?  Data Type  Example Value 

Yes  String (column reference)  myValues 
Include Page 

 EXAMPLE  Statistical Functions 

 EXAMPLE  Statistical Functions 

