SQL SUM() Function
The SQL SUM() Function
The SUM() function is used to calculate the total sum of values within a specified numeric column.
The SUM() function ignores NULL values in the column.
The following SQL returns the sum of the Quantity field in the "OrderDetails" table:
SUM() Syntax
SELECT SUM(column_name)
FROM table_name
WHERE condition;
Demo Database
Below is a selection from the OrderDetails table used in the examples:
| OrderDetailID | OrderID | ProductID | Quantity |
|---|---|---|---|
| 1 | 10248 | 11 | 12 |
| 2 | 10248 | 42 | 10 |
| 3 | 10248 | 72 | 5 |
| 4 | 10249 | 14 | 9 |
| 5 | 10249 | 51 | 40 |
Add a WHERE Clause
You can add a WHERE clause to specify conditions.
The following SQL returns the sum of the Quantity field for the product with ProductID = 11, in the "OrderDetails" table:
Use an Alias
Give the summarized column a name by using the AS keyword.
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:
Example
SELECT OrderID, SUM(Quantity) AS [Total Quantity]
FROM OrderDetails
GROUP BY OrderID;
Try it Yourself »
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" table costs 10 dollars, we can find the total earnings in dollars by multiply each quantity with 10:
Example
Use an expression inside the SUM() function:
SELECT SUM(Quantity * 10)
FROM OrderDetails;
Try it Yourself »
We can also join the "OrderDetails" table with the "Products" table to find the actual price, instead of assuming it is 10 dollars:
Example
Join OrderDetails with
Products, and use SUM() to find the total amount:
SELECT SUM(Price * Quantity)
FROM OrderDetails
LEFT JOIN Products ON OrderDetails.ProductID = Products.ProductID;
Try it Yourself »
You will learn more about Joins later in this tutorial.
