log10-transact-sql.md

description	LOG10 (Transact-SQL)
title	LOG10 (Transact-SQL) | Microsoft Docs
ms.custom
ms.date	03/06/2017
ms.prod	sql
ms.prod_service	database-engine, sql-database, sql-data-warehouse, pdw
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ms.technology	t-sql
ms.topic	reference
f1_keywords	LOG10 LOG10_TSQL
dev_langs	TSQL
helpviewer_keywords	float expressions LOG10 function base-10 logarithms logarithm of expression
ms.assetid	1eb7fb34-1937-4a39-a936-f5c0c7c7e06f
author	cawrites
ms.author	chadam
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)