LOG2() Function in MySQL
Last Updated :
01 Oct, 2020
In this article, we are going to cover the LOG2() function that means it will calculate the logarithm of a specific number with base 2.
Pre-requisite :LOG function
LOG2() function in MySQL is used to calculate the natural logarithm of a specific number with base 2. The number must be >0 Otherwise it will return NULL.
Syntax :
LOG2( X )
Parameter :
LOG2() function accepts one parameter which is described below as following.
- X –A number whose logarithm value with base 2 we want to calculate . It should be positive number.
Returns :
It returns the natural logarithm of given number x with base 2.
Example-1 :
Logarithm of given number with base 2 using LOG2() function.
SELECT LOG2(16) AS Log2_Val;
Output :
Example-2 :
Logarithm of 0 using LOG2() function.
SELECT LOG2(0) AS Log2_Val;
Output :
Example-3 :
The LOG2 function can also be used to find the logarithmic value with base 2 of a column data. To demonstrate create a table named Product.
CREATE TABLE Product
(
Product_id INT AUTO_INCREMENT,
Product_name VARCHAR(100) NOT NULL,
Buying_price DECIMAL(13,2) NOT NULL,
Selling_price DECIMAL(13,2) NOT NULL,
Service_grade Decimal(6,2) NOT NULL,
PRIMARY KEY(Product_id)
);
Now inserting some data to the Product table :
INSERT INTO Product
(Product_name, Buying_price, Selling_price, Service_grade)
VALUES
('Touring Bike' ,2019.00 ,3009.6 ,0.89 ) ,
('Mountain Bike' ,3019.50 ,4000.56 ,1.00 ) ,
('Road Bike' ,1019.20 ,2000.56 ,-0.89 ) ,
('Road Bicycle',1019.50 ,1500.56 ,-1.50 ) ,
('Racing Bicycle',3019.50 ,4000.56 ,2.00) ;
Showing all data in Product table :
Select * from Product;
Product_id |
Product_name |
Buying_price |
Selling_price |
Service_grade |
1 |
Touring Bike |
2019.00 |
3009.60 |
0.89 |
2 |
Mountain Bike |
3019.50 |
4000.56 |
1.00 |
3 |
Road Bike |
1019.20 |
2000.56 |
-0.89 |
4 |
Road Bicycle |
1019.50 |
1500.56 |
-1.50 |
5 |
Racing Bicycle |
3019.50 |
4000.56 |
2.00 |
Now, we are going to find the logarithmic values with base 2 for all the records present in the Service_grade column.
Select
Product_id,
Product_name,
Buying_price,
Selling_price,
Service_grade,
LOG2(Service_grade) AS GRADELOG2
FROM Product;
Output :
Product_id |
Product_name |
Buying_price |
Selling_price |
Service_grade |
GRADELOG2 |
1 |
Touring Bike |
2019.00 |
3009.60 |
0.89 |
-0.16812275880832692 |
2 |
Mountain Bike |
3019.50 |
4000.56 |
1.00 |
0 |
3 |
Road Bike |
1019.20 |
2000.56 |
-0.89 |
NULL |
4 |
Road Bicycle |
1019.50 |
1500.56 |
-1.50 |
NULL |
5 |
Racing Bicycle |
3019.50 |
4000.56 |
2.00 |
1 |
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