MySQL - PI() Function

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The MySQL PI() function returns the (pi) value. The value 'Pi' is mathematically defined as the ratio of a circle's circumference to its diameter. It is a constant value, and equal to 3.141592653589793... It is an irrational number since it is non-terminating and non-repeating decimal.

This function does not accept any arguments and returns the approximated value of 'Pi' up to 6 decimal places, i.e. 3.141593. You can also perform various numerical operations using this function for mathematical calculations on the data.

Syntax

Following is the syntax of this function −

PI();

Parameters

This function does not accept any parameters.

Return Value

This function returns the mathematical constant (pi) value.

Example

The following query uses MySQL PI() function to retrieve the mathematical constant (pi) −

SELECT PI() As Result;

Output

This will produce the following result −

Result
3.141593

Example

Following is another example of this function, where we are calculating the ceiling value (smallest integer greater than or equal to) of the mathematical constant −

SELECT CEILING(PI()) As Result;

Output

Following is the output −

Result
4

Example

By default, this function prints up to 7 decimal places you can print more digits as shown below −

SELECT PI()+0.000000000000000 As Result;

Output

The output is displayed as follows −

Result
3.141592653589793

Example

In the following query, we are creating a MySQL table named SHAPES using the CREATE statement −

CREATE TABLE SHAPES (
   ID int,
   NAME varchar(20),
   COLOUR varchar(20),
   RADIUS int,
   PRIMARY KEY(ID)
);

The following query inserts 5 records into above created table −

INSERT INTO SHAPES (ID,NAME,COLOUR,RADIUS) VALUES 
(1, 'CIRCLE_b', 'BLUE', 10),
(2, 'CIRCLE_y', 'YELLOW', 20),
(3, 'CIRCLE_g', 'GREEN', 30),
(4, 'CIRCLE_w', 'WHITE', 40),
(5, 'CIRCLE_o', 'ORANGE', 50);	

Execute the following query to display all the records present in the SHAPES table −

Select * From SHAPES;

Following is the SHAPES table −

ID	NAME	COLOUR	RADIUS
1	CIRCLE_b	BLUE	10
2	CIRCLE_y	YELLOW	20
3	CIRCLE_g	GREEN	30
4	CIRCLE_w	WHITE	40
5	CIRCLE_o	ORANGE	50

Now, we are using the PI() function to calculate the area of circles −

SELECT *, PI()*radius*radius as AREA FROM SHAPES;

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

ID	NAME	COLOUR	RADIUS	AREA
1	CIRCLE_b	BLUE	10	314.159265
2	CIRCLE_y	YELLOW	20	1256.637061
3	CIRCLE_g	GREEN	30	2827.433388
4	CIRCLE_w	WHITE	40	5026.548246
5	CIRCLE_o	ORANGE	50	7853.981634