SQL AVG() Function
The SQL AVG() Function
The AVG() function returns the average value of a numeric column.
Note: NULL values are ignored.
Syntax
SELECT AVG(column_name)
FROM table_name
WHERE condition;
Demo Database
Below is a selection from the Products table used in the examples:
| ProductID | ProductName | SupplierID | CategoryID | Unit | Price |
|---|---|---|---|---|---|
| 1 | Chais | 1 | 1 | 10 boxes x 20 bags | 18 |
| 2 | Chang | 1 | 1 | 24 - 12 oz bottles | 19 |
| 3 | Aniseed Syrup | 1 | 2 | 12 - 550 ml bottles | 10 |
| 4 | Chef Anton's Cajun Seasoning | 2 | 2 | 48 - 6 oz jars | 22 |
| 5 | Chef Anton's Gumbo Mix | 2 | 2 | 36 boxes | 21.35 |
Add a WHERE Clause
You can add a WHERE clause to specify conditions:
Example
Return the average price of products in category 1:
SELECT AVG(Price)
FROM Products
WHERE CategoryID = 1;
Try it Yourself »
Use an Alias
Give the AVG column a name by using the AS keyword.
Example
Name the column "average price":
SELECT AVG(Price) AS [average price]
FROM Products;
Try it Yourself »
Higher Than Average
To list all records with a higher price than average, we can use the
AVG() function in a sub query:
Example
Return all products with a higher price than the average price:
SELECT * FROM Products
WHERE price >
(SELECT AVG(price) FROM Products);
Try it Yourself »
Use AVG() with GROUP BY
Here we use the AVG() function and the
GROUP BY clause, to return the average price
for each category in the Products table:
Example
SELECT AVG(Price) AS AveragePrice, CategoryID
FROM Products
GROUP BY CategoryID;
Try it Yourself »
You will learn more about the
GROUP BY clause later in this tutorial.
