SQL Avg

The SQL AVG() Function

The average value of a numerical column is returned by the AVG() function.

Find the average price of all products:

				
					SELECT AVG(Price)
FROM Products;

Note: NULL values are ignored.

				
					SELECT AVG(column_name)
FROM table_name
WHERE condition;

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

A WHERE clause can be added to establish conditions:

Return the average price of products in category 1:

				
					SELECT AVG(Price)
FROM Products
WHERE CategoryID = 1;

Use the AS keyword to assign a name to the summary column.

Name the column “average price”:

				
					SELECT AVG(Price) AS [average price]
FROM Products;

By using the AVG() function in a subquery, we may list all records that have a price higher than average:

Return all products with a higher price than the average price:

				
					SELECT * FROM Products
WHERE price > (SELECT AVG(price) FROM Products);

Here, we retrieve the average price for each category in the Products table using the GROUP BY clause and the AVG() function:

				
					SELECT AVG(Price) AS AveragePrice, CategoryID
FROM Products
GROUP BY CategoryID;

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