PostgreSQL Tutorial: SQRT Function

July 5, 2024

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.

See more

PostgreSQL Tutorial: Math Functions

PostgreSQL Documentation: Mathematical Functions and Operators