PostgreSQL – AVG() Function
PostgreSQL provides an AVG() function to calculate the average value of a set. The AVG() function is one of the most frequently used aggregate functions in PostgreSQL. The AVG() function enables users to calculate the average value of a numeric column.
Syntax: AVG(column)
Example 1:
We will be using the payment
table in the dvdrental sample database for demonstration. In this example we will query to know the average amount that customers paid, using the AVG() function in the amount
column as follows:
SELECT to_char( AVG (amount), '99999999999999999D99' ) AS average_amount FROM payment;
Output:
Note: We used the to_char()
function to convert the result into a formatted string.
Example 2:
We will be using the payment
table in the dvdrental sample database for demonstration. In this example we will query to know the average amount paid by each customer using the command below:
SELECT customer.customer_id, first_name, last_name, to_char( AVG (amount), '99999999999999999D99' ) AS average_amount FROM payment INNER JOIN customer ON customer.customer_id = payment.customer_id GROUP BY customer.customer_id ORDER BY customer_id;
Output: