PostgreSQL SQRT() Function

Summary: in this tutorial, you will learn how to use the PostgreSQL SQRT() function to calculate the square root of a number.

Introduction to the PostgreSQL SQRT() function

The SQRT() function is a powerful mathematical function that allows you to calculate the square root of a number.

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

SQRT(number)

In this syntax, the number is a numeric value for which you want to calculate the square root

The SQRT() function returns the square root of the input number.

PostgreSQL SQRT() function examples

Let’s take some examples of using the SQRT() function.

1) Basic SQRT() function example

The following example uses the SQRT() function to return the square root of 25:

SELECT SQRT(25) AS result;

Output:

result
--------
      5
(1 row)

The query returns the square root of 25, which is 5.

2) Using PostgreSQL SQRT() function to calculate distance

Suppose you have a table called coordinates that consists of columns x and y representing the coordinates of points in two-dimensional space:

-- Create coordinates table
CREATE TABLE coordinates (
    id SERIAL PRIMARY KEY,
    x NUMERIC,
    y NUMERIC
);

-- Insert sample data
INSERT INTO coordinates (x, y) VALUES
    (3, 4),
    (-2, 5),
    (0, 0),
    (8, -6),
    (-1.5, 2.5)
RETURNING *;

Output:

id |  x   |  y
----+------+-----
  1 |    3 |   4
  2 |   -2 |   5
  3 |    0 |   0
  4 |    8 |  -6
  5 | -1.5 | 2.5
(5 rows)

The following query uses the SQRT() function to calculate the distance of each point from the origin (0,0):

SELECT SQRT(x * x + y * y) AS distance_from_origin
FROM coordinates;

Output:

distance_from_origin
----------------------
    5.000000000000000
    5.385164807134504
    0.000000000000000
   10.000000000000000
    2.915475947422650
(5 rows)

Summary

• Use the PostgreSQL SQRT() function to calculate the square root of a number.