SQL SUM() AND AVG()

In SQL, SUM() and AVG() functions are used to calculate total and average values in numeric columns.

SQL SUM() Function

The SQL SUM() function is used to calculate the sum of numeric values in a column. For example,

SELECT SUM(amount) AS total_sales
FROM Orders;

Here, the SQL command returns the sum of amounts of all orders.

Let's take a look at another example.

SELECT SUM(amount) AS total_of_cus4
FROM Orders
WHERE customer_id = 4;

Here, the SQL command returns the total amount to be paid by the customer having id 4.

SQL AVG() Function

The SQL AVG() function is used to calculate the average of numeric values in a column. For example,

SELECT AVG(age) AS average_age
FROM Customers;

Here, the SQL command returns the average age of all customers.

Let's take a look at another example

SELECT DISTINCT customer_id, AVG(amount) AS average_spends
FROM Orders
GROUP BY customer_id;

Here, the SQL command returns the average spending of each customer.

Recommended readings

• SQL Aliases
• SQL GROUP BY
• SQL DISTINCT