log10-transact-sql.md

title	LOG10 (Transact-SQL)
description	LOG10 (Transact-SQL)
author	markingmyname
ms.author	maghan
ms.date	03/06/2017
ms.prod	sql
ms.technology	t-sql
ms.topic	reference
f1_keywords	LOG10 LOG10_TSQL
helpviewer_keywords	float expressions LOG10 function base-10 logarithms logarithm of expression
dev_langs	TSQL
monikerRange	>= aps-pdw-2016 || = azuresqldb-current || = azure-sqldw-latest || >= sql-server-2016 || >= sql-server-linux-2017 || = azuresqldb-mi-current

LOG10 (Transact-SQL)

[!INCLUDE sql-asdb-asdbmi-asa-pdw]

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

Transact-SQL Syntax Conventions

Syntax

LOG10 ( float_expression )  

[!INCLUDEsql-server-tsql-previous-offline-documentation]

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)