T-SQL » Functions » STDEVP

Syntax:
SELECT STDEVP ( field ) [ AS expression ]
FROM table
[ WHERE criteria ]
[ GROUP BY grouping_expression ]
[ HAVING criteria ]
field
The name of the column that the standard deviation of the values is to be taken.
expression
The name to be displayed for the resulting standard deviation.
table
The name of the table the information is being retrieved from.
criteria
The condition(s) that dictate which rows are to be calculated.
grouping_expression
An optional parameter that specifies a set of columns on which to group matching data.

The STDEVP function finds the standard deviation by using all of the values in a field.

In comaparison, the STDEV function only uses a portion, called a sample, of the values to calculate the standard deviation. There must be at least two values in the field or the standard deviation will not be calculated and a NULL value is returned.

Examples

Code:
SELECT STDEVP(Age) AS DevAge
FROM MediCarePatients;
Output:
DevAge
19.21803

(1 row(s) affected)
Explanation:

This code finds the standard deviation of the age for all MediCare patients in a hospital and stores that information in 'DevAge'.

Language(s): MS SQL Server

See Also: