log10-transact-sql.md

title	LOG10 (Transact-SQL) | Microsoft Docs
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ms.date	03/06/2017
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LOG10 (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-all_md]

Returns the base-10 logarithm of the specified float expression.

Transact-SQL Syntax Conventions

Syntax

-- Syntax for SQL Server, Azure SQL Database, Azure SQL Data Warehouse, Parallel Data Warehouse  
  
LOG10 ( float_expression )  

Arguments

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

Return Types

float

Remarks

The LOG10 and POWER functions are inversely related to one another. For example, 10 ^ LOG10(n) = n.

Examples

A. Calculating the base 10 logarithm for a variable.

The following example calculates the LOG10 of the specified variable.

DECLARE @var float;  
SET @var = 145.175643;  
SELECT 'The LOG10 of the variable is: ' + CONVERT(varchar,LOG10(@var));  
GO  

[!INCLUDEssResult]

The LOG10 of the variable is: 2.16189      
  
(1 row(s) affected)  

B. Calculating the result of raising a base-10 logarithm to a specified power.

The following example returns the result of raising a base-10 logarithm to a specified power.

SELECT POWER (10, LOG10(5));   

[!INCLUDEssResult]

-----------  
5  
  
(1 row(s) affected)  

Examples: [!INCLUDEssSDWfull] and [!INCLUDEssPDW]

C: Calculating the base 10 logarithm for a value.

The following example calculates the LOG10 of the specified value.

SELECT LOG10(145.175642);  

[!INCLUDEssResult]

-------------------

2.16

See Also

Mathematical Functions (Transact-SQL)
POWER (Transact-SQL)
LOG (Transact-SQL)