MySQL LN() function

In this context, we will learn how we can use the MySQL LN() function with proper syntax and good examples.

Introduction of MySQL LN() function

For evaluation of the natural logarithm of a mentioned number with base e, the LN() function in MySQL is used. It will return NULL when the number is greater than 0.

Syntax of the MySQL LN() function

The syntax of the MySQL LN() function is given as follows:

LN(Y);

Parameters or arguments used in MySQL LN() function:

Only one parameter is accepted by LN() function, as mentioned above in the syntax and described below as follows.

Y: This is the number whose logarithm value with base e we want to calculate. It should be a positive number.

Returns: It will return the natural logarithm of the given number Y with base e.

The application used for LN() function:

The LN() function can be used in the given below MySQL versions:

• MySQL 5.7
• MySQL 5.6
• MySQL 5.5
• MySQL 5.1
• MySQL 5.0
• MySQL 4.1
• MySQL 4.0
• MySQL 3.23

Examples of MySQL LN() function:

Now, we will look into some examples of MySQL LN functions.

Example 1:

Here, we will find the logarithm of the given numbers with base e using the LN() function in MySQL.

SELECT LN(1000) AS Ln_Val ;

Output:

LN_VAL
6.907755278982137
1 row in set (0.00 sec)

Example 2:

Here, we will find the logarithm of 0 with base e using the LN() function in MySQL.

SELECT LN(0) AS Ln_Val ;

Output:

LN_VAL
NULL
1 row in set (0.00 sec)

Example 3:

The LN function can also be used to find the logarithmic value with base e of column data. To demonstrate, create a table named Commodity.

CREATE TABLE Commodity(
Commodity_id INT AUTO_INCREMENT,  
Commodity_name VARCHAR(100) NOT NULL,
Purchasing_price DECIMAL(13, 2) NOT NULL,
Selling_price DECIMAL(13, 2) NOT NULL,
Service_grade Decimal(6, 2) NOT NULL,
PRIMARY KEY(Commodity_id)
);

Inserting into the Commodity table:

Now we will add some data to the Commodity table –

INSERT INTO  
Commodity(Commodity_name, Purchasing_price, Selling_price, Service_grade)
VALUES
('Touring Bike,' 20000.00, 30050.00, 4.17 ),
('Mountain Bike,' 30005.50, 40000.56, 10.00 ),
('Road Bike,' 10000.20, 21000.56, -3.59 ),
('Road Bicycle,' 15200.50, 18000.00, -0.50 ),
('Racing Bicycle,' 30500.50, 45000.00, 3.00) ;

Reading data from the table :

Now we will Show all data in Commodity Table –

Select * from Commodity;

Output:

Now, we are going to find the logarithmic values with base e for all the records present in the Service_grade column.

Select Commodity_id, Commodity_name, Purchasing_price,  
Selling_price, Service_grade,
LN(Service_grade) AS GRADELOGN  
FROM Commodity;

Output:

Summary:

In this context, we have learned how we can use the MySQL LN() function to find the LN values from given arguments respectively.