SQL Server LOG() Function

The LOG() function in SQL Server calculates the logarithm of a number. You can specify the base of the logarithm, providing flexibility for various mathematical calculations.

LOG(): Definition and Usage

Logarithms are fundamental mathematical operations used to solve exponential equations. The LOG() function in SQL Server allows you to compute both natural logarithms (base *e*) and logarithms to other bases. The natural logarithm (base *e*) is the default if you only provide a single number as input; otherwise you specify the base as the second argument.

Syntax

-- For SQL Server 2012 and later:
LOG ( number, base )

-- For Azure SQL Database, Azure SQL Data Warehouse, Parallel Data Warehouse:
LOG ( number ) --This will calculate the natural logarithm (base e)
      

Parameter Values

Examples

Natural Logarithm (Base e)

This calculates the natural logarithm (base *e*) of 2.

SELECT LOG(2);
      

0.693147180559945 (The exact value might vary slightly depending on your SQL Server version)
      

Logarithm with a Specified Base

This calculates the logarithm of 2 with base 4.

SELECT LOG(2, 4);
      

0.5