STDEVP (Transact-SQL)
Applies to:
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Azure Synapse Analytics
Analytics Platform System (PDW)
SQL analytics endpoint in Microsoft Fabric
Warehouse in Microsoft Fabric
Returns the statistical standard deviation for the population for all values in the specified expression.
Transact-SQL syntax conventions
Syntax
-- Aggregate Function Syntax
STDEVP ( [ ALL | DISTINCT ] expression )
-- Analytic Function Syntax
STDEVP ([ ALL ] expression) OVER ( [ partition_by_clause ] order_by_clause)
Note
To view Transact-SQL syntax for SQL Server 2014 (12.x) and earlier versions, see Previous versions documentation.
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.
OVER ( [ partition_by_clause ] order_by_clause)
partition_by_clause divides the result set produced by the FROM clause into partitions to which the function is applied. If not specified, the function treats all rows of the query result set as a single group. order_by_clause determines the logical order in which the operation is performed. order_by_clause is required. For more information, see OVER Clause (Transact-SQL).
Return Types
float
Remarks
If STDEVP is used on all items in a SELECT statement, each value in the result set is included in the calculation. STDEVP can be used with numeric columns only. Null values are ignored.
STDEVP is a deterministic function when used without the OVER and ORDER BY clauses. It is nondeterministic when specified with the OVER and ORDER BY clauses. For more information, see Deterministic and Nondeterministic Functions.
Examples
A: Using STDEVP
The following example returns the standard deviation for the population for all bonus values in the SalesPerson
table in the AdventureWorks2022 database.
SELECT STDEVP(Bonus)
FROM Sales.SalesPerson;
GO
Examples: Azure Synapse Analytics and Analytics Platform System (PDW)
B: Using STDEVP
The following example returns the STDEVP
of the sales quota values in the table dbo.FactSalesQuota
. The first column contains the standard deviation of all distinct values and the second column contains the standard deviation of all values including any duplicates values.
-- Uses AdventureWorks
SELECT STDEVP(DISTINCT SalesAmountQuota)AS Distinct_Values, STDEVP(SalesAmountQuota) AS All_Values
FROM dbo.FactSalesQuota;SELECT STDEVP(DISTINCT Quantity)AS Distinct_Values, STDEVP(Quantity) AS All_Values
FROM ProductInventory;
Here is the result set.
Distinct_Values All_Values
---------------- ----------------
397676.79 397226.44
C. Using STDEVP with OVER
The following example returns the STDEVP
of the sales quota values for each quarter in a calendar year. Notice that the ORDER BY
in the OVER
clause orders the STDEVP
and the ORDER BY
of the SELECT
statement orders the result set.
-- Uses AdventureWorks
SELECT CalendarYear AS Year, CalendarQuarter AS Quarter, SalesAmountQuota AS SalesQuota,
STDEVP(SalesAmountQuota) OVER (ORDER BY CalendarYear, CalendarQuarter) AS StdDeviation
FROM dbo.FactSalesQuota
WHERE EmployeeKey = 272 AND CalendarYear = 2002
ORDER BY CalendarQuarter;
Here is the result set.
Year Quarter SalesQuota StdDeviation
---- ------- ---------------------- -------------------
2002 1 91000.0000 0.00
2002 2 140000.0000 24500.00
2002 3 70000.0000 29329.55
2002 4 154000.0000 34426.55
See Also
Aggregate Functions (Transact-SQL)
OVER Clause (Transact-SQL)