# PI() function: π

SELECT PI()
Ouput is 3.141593

This is a mathematical constant (π) and the value displayed by MySQL is for 7 digits after decimal but internaly stores double-precision value of PI.

## PI() with DEGREES()

DEGREES function converts redian to degree
SELECT DEGREES(PI()); // Ouput is 180
SELECT DEGREES(PI()/2); // Ouput is 90
SELECT DEGREES(PI()/3); // Ouput is 59.99999

## PI with SIN() COS()

We can get sine of any value in radians by using sin(), note that sin(x) takes input in redian. Value of x is in redian.
SELECT SIN(PI()); // Ouput is 1.2246467991473532e-16
We can use use ROUND Function to rounds to output
SELECT ROUND(SIN(PI())); // Output is 0
SELECT ROUND(SIN(PI()/2)); // Output is 1
We will allow some decimal places to be shown as the value of SIN varies between 0 and 1.
SELECT ROUND( SIN( PI( ) /3 ), 3 ) //Output is 0.866
SELECT ROUND( SIN( PI( ) /4 ) , 4 ) // Output is 0.7071

We can try COS values
SELECT ROUND( COS( PI( ) /3 ), 3 ) //Output is  0.500
SELECT ROUND( COS( PI( ) /2 ), 3 ) // Output is 0.000

▼ More on Math functions in SQL

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