power-transact-sql.md

title	POWER (Transact-SQL) | Microsoft Docs
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ms.date	03/13/2017
ms.prod	sql-non-specified
ms.prod_service	database-engine, sql-database, sql-data-warehouse, pdw
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ms.component	t-sql|functions
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ms.suite	sql
ms.technology	database-engine
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ms.topic	language-reference
f1_keywords	POWER_TSQL POWER
dev_langs	TSQL
helpviewer_keywords	POWER function
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author	edmacauley
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POWER (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-all-md]

Returns the value of the specified expression to the specified power.

Transact-SQL Syntax Conventions

Syntax

POWER ( float_expression , y )  

Arguments

float_expression
Is an expression of type float or of a type that can be implicitly converted to float.

y
Is the power to which to raise float_expression. y can be an expression of the exact numeric or approximate numeric data type category, except for the bit data type.

Return Types

Returns the same type as submitted in float_expression. For example, if a decimal(2,0) is submitted as float_expression, the result returned is decimal(2,0).

Examples

A. Using POWER to return the cube of a number

The following example demonstrates raising a number to the power of 3 (the cube of the number).

DECLARE @input1 float;  
DECLARE @input2 float;  
SET @input1= 2;  
SET @input2 = 2.5;  
SELECT POWER(@input1, 3) AS Result1, POWER(@input2, 3) AS Result2;  

[!INCLUDEssResult]

Result1                Result2  
---------------------- ----------------------  
8                      15.625  
  
(1 row(s) affected)  

B. Using POWER to show results of data type conversion

The following example shows how the float_expression preserves the data type which can return unexpected results.

SELECT   
POWER(CAST(2.0 AS float), -100.0) AS FloatResult,  
POWER(2, -100.0) AS IntegerResult,  
POWER(CAST(2.0 AS int), -100.0) AS IntegerResult,  
POWER(2.0, -100.0) AS Decimal1Result,  
POWER(2.00, -100.0) AS Decimal2Result,  
POWER(CAST(2.0 AS decimal(5,2)), -100.0) AS Decimal2Result;  
GO  

[!INCLUDEssResult]

FloatResult            IntegerResult IntegerResult Decimal1Result Decimal2Result Decimal2Result  
---------------------- ------------- ------------- -------------- -------------- --------------  
7.88860905221012E-31   0             0             0.0            0.00           0.00  

C. Using POWER

The following example returns POWER results for 2.

DECLARE @value int, @counter int;  
SET @value = 2;  
SET @counter = 1;  
  
WHILE @counter < 5  
   BEGIN  
      SELECT POWER(@value, @counter)  
      SET NOCOUNT ON  
      SET @counter = @counter + 1  
      SET NOCOUNT OFF  
   END;  
GO  

[!INCLUDEssResult]

-----------   
2             
  
(1 row(s) affected)  
  
-----------   
4             
  
(1 row(s) affected)  
  
-----------   
8             
  
(1 row(s) affected)  
  
-----------   
16            
  
(1 row(s) affected)  

Examples: [!INCLUDEssSDWfull] and [!INCLUDEssPDW]

D: Using POWER to return the cube of a number

The following example shows returns POWER results for 2.0 to the 3rd power.

SELECT POWER(2.0, 3);  

[!INCLUDEssResult]

------------ 
8.0

See Also

decimal and numeric (Transact-SQL)
float and real (Transact-SQL)
int, bigint, smallint, and tinyint (Transact-SQL)
Mathematical Functions (Transact-SQL)
money and smallmoney (Transact-SQL)