Syntax:
LN(X)

Returns the natural logarithm of X; that is, the base-e logarithm of X.
If X is less than or equal to 0.0E0, the function returns NULL and a
warning "Invalid argument for logarithm" is reported. Returns NULL if X
is NULL.

URL: https://dev.mysql.com/doc/refman/8.0/en/mathematical-functions.html

