LN

Description

The LN function is used to calculate the natural logarithm (logarithm to the base e) of a given numerical expression. Natural logarithms have wide applications in fields such as mathematics, physics, and engineering, for example, when dealing with problems of exponential growth and decay.

Syntax

LN(expr)

Parameters

• expr: The numerical expression for which the natural logarithm needs to be calculated, of type double.

Return Value

Returns the calculated result, of type double.

Example Usage

1. Calculate the natural logarithm of a constant value:

   SELECT LN(3.1415926);
   

Result:

1.144729868791239

2. Calculate the natural logarithm of a negative number (result is NULL):

   SELECT LN(-1);
   

Result:

null

3. Calculate the natural logarithm of a larger number:

   SELECT LN(1000000);
   

Result:

 13.815510557964274

4. Calculate the natural logarithm of e (the result should be close to 1):

   SELECT LN(EXP(1));
   

Result:

1.0

Notes

• When the expr parameter is negative, the LN function will return NULL because negative numbers do not have a natural logarithm in the real number domain.
• When the expr parameter is 0, the LN function will also return NULL because 0 does not have a natural logarithm.
• When using the LN function, please ensure that the passed expression is a valid double type value, otherwise it may result in incorrect calculations or return NULL.