PostgreSQL RADIANS() Function

Summary: in this tutorial, you will learn how to use the PostgreSQL RADIANS() function to convert degrees to radians.

Introduction to the PostgreSQL RADIANS() function

The RADIANS() function converts degrees to radians.

Here’s the basic syntax of the RADIANS() function:

RADIANS(degrees_value)

In this syntax, the degrees_value is a value in degrees that you want to convert to radians. The function returns the degrees_value converted to radians.

If the degrees_value is NULL, the function returns NULL.

PostgreSQL RADIANS() function examples

Let’s explore some examples of using the RADIANS() function.

1) Basic RADIANS() function example

The following example uses the RADIANS() function to convert 180 degrees to its equivalent in radians, resulting in PI value:

SELECT RADIANS(180);

Output:

radians
-------------------
 3.141592653589793
(1 row)

2) Using the RADIANS() function with table data

We’ll show you how to use the RADIANS with data in a table.

First, create a new table called angles to store angle data in radians:

CREATE TABLE angles (
    id SERIAL PRIMARY KEY,
    angle_degrees NUMERIC
);

Second, insert some rows into the angles table:

INSERT INTO angles (angle_degrees)
VALUES
    (45),
    (60),
    (90),
    (NULL)
RETURNING *;

Output:

id | angle_degrees
----+---------------
  1 |            45
  2 |            60
  3 |            90
  4 |          null
(4 rows)

Third, use the RADIANS() function to convert the values in the angle_degrees column to radians:

SELECT
    id,
    angle_degrees,
    RADIANS(angle_degrees) AS angle_radians
FROM
    angles;

Output:

id | angle_degrees |   angle_radians
----+---------------+--------------------
  1 |            45 | 0.7853981633974483
  2 |            60 | 1.0471975511965976
  3 |            90 | 1.5707963267948966
  4 |          null |               null
(4 rows)

Summary

Use the PostgreSQL RADIANS() function to convert degrees to radians.