SQL SUM() Function

The SQL SUM() Function

The SUM() function returns the total sum of a numeric column.

SELECT SUM(Quantity)
FROM OrderDetails;

Syntax

SELECT SUM(column_name)
FROM table_name
WHERE condition;

Demo Database

Below is a selection from the OrderDetails table used in the examples:

Add a WHERE Clause

You can add a WHERE clause to specify conditions:

SELECT SUM(Quantity)
FROM OrderDetails
WHERE ProductId = 11;

Use an Alias

Give the summarized column a name by using the AS keyword.

SELECT SUM(Quantity) AS total
FROM OrderDetails;

Use SUM() with GROUP BY

Here we use the SUM() function and the GROUP BY clause, to return the Quantity for each OrderID in the OrderDetails table:

SELECT OrderID, SUM(Quantity) AS [Total Quantity]
FROM OrderDetails
GROUP BY OrderID;

You will learn more about the GROUP BY clause later in this tutorial.

SUM() With an Expression

The parameter inside the SUM() function can also be an expression.

If we assume that each product in the OrderDetails column costs 10 dollars, we can find the total earnings in dollars by multiply each quantity with 10:

SELECT SUM(Quantity * 10)
FROM OrderDetails;

We can also join the OrderDetails table to the Products table to find the actual amount, instead of assuming it is 10 dollars:

SELECT SUM(Price * Quantity)
FROM OrderDetails
LEFT JOIN Products ON OrderDetails.ProductID = Products.ProductID;