LN

     This is based on natural or base e logarithm.

     Syntax: ln (value)           -- here value must be greater than zero which is positive only.

     Ex:

          SQL> select ln(1), ln(2), ln(null) from dual;

                        LN(1)      LN(2)      LN(NULL)

-------      -------      ------------

                            0        .693147181

          Ln and Exp are reciprocal to each other.

            EXP (3) = 20.0855369

            LN (20.0855369) = 3