Example
Return the natural logarithm of 2:
SELECT LOG(2);
Definition and Usage
The LOG() function returns the natural logarithm of a specified number, or the logarithm of the number to the specified base.
From SQL Server 2012, you can also change the base of the logarithm to another value by using the optional base parameter.
Note: Also look at the EXP() function.
Syntax
LOG(number, base) — Syntax for SQL Server
OR :
LOG(number) — Syntax for Azure SQL Database, Azure SQL Data Warehouse, Parallel Data Warehouse