PostgreSQL POWER() Function

Summary: in this tutorial, you will learn how to use the PostgreSQL POWER() function to raise a number to a specific power.

Introduction to PostgreSQL POWER() function

The POWER() function allows you to raise a number to a specific power. Here’s the basic syntax of the POWER() function:

POWER(base, exponent)

In this syntax:

• base: This is the base number
• exponent: This is the exponent to which you want to raise the base number.

The POWER() function returns a numeric value representing the result of raising the base number to a specified exponent. It returns NULL if either base or exponent is NULL.

PostgreSQL POWER() function examples

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

1) Basic POWER() function examples

The following example uses the POWER() function to raise the number to the power of 3:

SELECT POWER(2,3) result;

Output:

result
--------
      8
(1 row)

Similarly, you can use the POWER() function with decimal values:

SELECT POWER(2.5, 2);

Output:

power
--------------------
 6.2500000000000000
(1 row)

2) Using the POWER() function with negative exponent

The following example uses the POWER() function with a negative exponent:

SELECT POWER(10, -2);

Output:

power
-------
  0.01
(1 row)

In this example, we raise 10 to the power of -2 resulting in 0.01.

3) Using the POWER() function with a fractional exponent

The following example uses the POWER() function to raise the number 2 to the power of 1.5:

SELECT POWER(2, 1.5);

Output:

power
--------------------
 2.8284271247461901
(1 row)

4) Using the POWER() function with table data

We’ll use the POWER() function to calculate compound interest.

First, create a table called investments to store the investment data:

CREATE TABLE investments (
    id SERIAL PRIMARY KEY,
    investment_amount NUMERIC NOT NULL,
    annual_interest_rate NUMERIC NOT NULL,
    years INT NOT NULL
);

Second, insert some rows into the investments table:

INSERT INTO investments (investment_amount, annual_interest_rate, years)
VALUES
    (1000, 5, 1),
    (2000, 7, 3),
    (5000, 4.5, 5)
RETURNING *;

Output:

id | investment_amount | annual_interest_rate | years
----+-------------------+----------------------+-------
  1 |              1000 |                    5 |     1
  2 |              2000 |                    7 |     3
  3 |              5000 |                  4.5 |     5
(3 rows)

Third, calculate the compound interest of each investment in the investments table:

SELECT
    investment_amount,
    annual_interest_rate,
    years,
    ROUND(investment_amount * POWER(1 + (annual_interest_rate / 100), years), 2) AS future_value
FROM
    investments;

Output:

investment_amount | annual_interest_rate | years | future_value
-------------------+----------------------+-------+--------------
              1000 |                    5 |     1 |      1050.00
              2000 |                    7 |     3 |      2450.09
              5000 |                  4.5 |     5 |      6230.91
(3 rows)

The query returns the initial investment details along with the calculated future value for each investment.

To calculate the compound interest of each investment:

• Calculate the interest rate using the POWER() function.
• Use the ROUND() function to round the future value to two decimal places.

Summary

• Use the PostgreSQL POWER() function to raise a number to a specific power.