STDEV (Transact-SQL)

STDEV (Transact-SQL)

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SQL Server 2005

SQL Server 2008 Books Online (October 2009)

STDEV (Transact-SQL)

Returns the statistical standard deviation of all values in the specified expression. May be followed by the OVER clause.

Topic link icon Transact-SQL Syntax Conventions

Syntax

STDEV ( [ ALL | DISTINCT ] expression )

Arguments

ALL: Applies the function to all values. ALL is the default.

DISTINCT: Specifies that each unique value is considered.

expression: Is a numeric expression. Aggregate functions and subqueries are not permitted. expression is an expression of the exact numeric or approximate numeric data type category, except for the bit data type.

Return Types

float

Remarks

If STDEV is used on all items in a SELECT statement, each value in the result set is included in the calculation. STDEV can be used with numeric columns only. Null values are ignored.

Examples

The following example returns the standard deviation for all bonus values in the SalesPerson table.

USE AdventureWorks;
GO
SELECT STDEV(Bonus)
FROM Sales.SalesPerson;
GO

Reference

Aggregate Functions (Transact-SQL)
OVER Clause (Transact-SQL)

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