SQL - LOG() Function

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The SQL LOG() 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. You can also pass two parameter in the LOG() function like LOG(X, B). If you do so, this function returns the natural logarithm of the X value to the base B.

Syntax

Following is the syntax of the SQL LOG() function −

LOG();

Following is the another syntax of LOG() function that accept the two number as a para meter −

SELECT LOG(X, B) AS alias_Name;

Parameters

• X − It is the number that needs to be found in the natural logarithm, and it should be greater than 0.

• B − It is optional; it is used for the base on which the natural logarithm is to be calculated, and it must be greater than 0.

Example

In the following example, we are calculating the value of LOG(10) using the SQL query.

Following is the SQL query −

SELECT lOG(10) AS 'LOG(10)';

Output

Following is the output of the above SQL query −

+--------------------+
|             LOG(10)|
+--------------------+
|    2.30258509299405|
+--------------------+

Example

In the following example, we are passing 0 and a negative value to the LOG() function if the value passed is 0 and a negative. Log will return a value null. In MySQL, it gives an error in the SQL.

Following is the query −

SELECT lOG(0) AS 'LOG(0)', LOG(2) AS 'LOG(-2)';

Output

On execution of the above SQL query, we get the error because the LOG() function in SQL returns an error if the argument is 0 or a negative value.

An invalid floating point operation occurred.

Example

In the following example, we are using the LOG() function and passing two parameters to it. The log() function returns the natural logarithm of the first number to the base of the second number.

Following is the SQL query −

SELECT lOG(10,2) AS log_of_10_base_2;

Output

Following is the output of the above SQL query −

+------------------+
| log_of_10_base_2 |
+------------------+
| 3.32192809488736 |
+------------------+

Example

In the following example, we are calculating the log(4) to the base 2 using the following SQL query −

Following is the SQL query −

SELECT LOG(4, 2) AS 'log2(4)';

Output

Following is the output of the above SQL query −

+---------+
| log2(4) |
+---------+
|       2 |
+---------+