POWER (Transact-SQL)

APPLIES TO: yesSQL Server (starting with 2008) yesAzure SQL Database yesAzure SQL Data Warehouse yesParallel Data Warehouse

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

Topic link icon 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

The return type depends on the input type of float_expression:

Input type Return type
float, real float
decimal(p, s) decimal(38, s)
int, smallint, tinyint int
bigint bigint
money, smallmoney money
bit, char, nchar, varchar, nvarchar float

If the result does not fit in the return type, an arithmetic overflow error occurs.

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;  

Here is the result set.

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  

Here is the result set.

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  

Here is the result set.

-----------   
2             

(1 row(s) affected)  

-----------   
4             

(1 row(s) affected)  

-----------   
8             

(1 row(s) affected)  

-----------   
16            

(1 row(s) affected)  

Examples: Azure SQL Data Warehouse and Parallel Data Warehouse

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);  

Here is the result set.

------------ 
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)