The standard natural logarithm function is supported, generating LN (expression) and returning a value of type float. When dragging a Natural Logarithm into a variable, the following tree element is created.
Variable Creation > Input > Variables: SQL Elements pane - Arithmetic > Natural Logarithm
Columns and/or other expressions can be moved over the (empty) branch of the tree.
There are no special properties for the Natural Logarithm function.
Consider a Case statement in conjunction with this function if zero or negative values may occur in the data, resulting in a SQL argument error.