MySQL - LN() Function

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The LN() function accepts a numerical value as a parameter and returns the natural logarithm of it. In other words, this function returns the base-e logarithm of the given value.

Logarithm is simply defined as the inverse of an exponent. Thus, the LN() function is also the inverse of EXP() function. The result of a logarithm is the power to which the base of the logarithm will be raised.

A logarithm can be represented as follows −

logba = p

Parameters

This function accepts the parameters as follows −

• a: any number
• b: base of the logarithm
• p: power to which the base is raised

Return Value

This function returns the natural logarithm of the given value.

Syntax

Following is the syntax of MySQL LN() function −

LN(x);

Example

The following query uses MySQL LN() function to calculate the natural logarithm (base e) of the value 9 −

SELECT LN(9) As Result;

Output

The output for the query above is produced as given below −

Result
2.1972245773362196

Example

If the value passed to the function is less than or equal to 0.0E0, it returns NULL.

Here, we are passing 0 as a parameter to this function −

SELECT LN(0) As Result;

Following is the output −

Result
NULL

Now, we are passing -3 to this function −

SELECT LN(-3) As Result;

Following is the output −

Result
NULL

Example

The MySQL LN() function is inverse of the EXP() function.

Here, we are passing 90 as a parameter to the EXP() function −

SELECT EXP(90) As Result;

The output will be displayed as below −

Result
1.2204032943178408e39

Now, we can use the output of above function as parameter to LN() function to retrieve the original value −

SELECT LN(1.2204032943178408e39) As Result;

Following is the output −

Result
90