SQL SUM() Function
The SUM() function returns the total sum of a numeric column.
Example​
Return the sum of all Quantity fields in the OrderDetails table:
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:
| 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:
Example​
Return the sum of the Quantity field for the product with ProductID 11:
SELECT SUM(Quantity)
FROM OrderDetails
WHERE ProductId = 11;
Use an Alias​
Give the summarized column a name by using the AS keyword.
Example​
Name the column "total":
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:
Example​
SELECT OrderID, SUM(Quantity) AS \[Total Quantity\]
FROM OrderDetails
GROUP BY OrderID;
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:
Example​
Use an expression inside the SUM() function:
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:
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;