Syntax
------ 
LOG(X), LOG(B,X)
 
Description
----------- 
If called with one parameter, this function returns the
natural
logarithm of X. If X is less than or equal to 0, then NULL
is
returned.
 
If called with two parameters, it returns the logarithm of X
to the base B. If B is 

URL: https://mariadb.com/kb/en/log/