LOG10 (Transact-SQL)

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric

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

Syntax

LOG10 ( float_expression )

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

float

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

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

Here's the result set.

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

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

SELECT POWER (10, LOG10(5));

Here's the result set.

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

The following example calculates the LOG10 of the specified value.

SELECT LOG10(145.175642);

Here's the result set.

-------------------  
2.16