How to calculate weekly average in SQL

SQL COUNT(), AVG() and SUM() Functions Previous Next The SQL COUNT(), AVG() and SUM() Functions The COUNT() function returns

How to calculate weekly average in SQL

SQL COUNT(), AVG() and SUM() Functions   Previous Next


The SQL COUNT(), AVG() and SUM() Functions

The COUNT() function returns the number of rows that matches a specified criterion.

COUNT() SyntaxSELECT COUNT(column_name)
FROM table_name
WHERE condition;

The AVG() function returns the average value of a numeric column.

AVG() SyntaxSELECT AVG(column_name)
FROM table_name
WHERE condition;

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

SUM() SyntaxSELECT SUM(column_name)
FROM table_name
WHERE condition;


Demo Database

Below is a selection from the "Products" table in the Northwind sample database: 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



COUNT() Example

The following SQL statement finds the number of products:

Example  SELECT COUNT(ProductID)
FROM Products; Try it Yourself »

Note: NULL values are not counted.


AVG() Example

The following SQL statement finds the average price of all products:

Example  SELECT AVG(Price)
FROM Products; Try it Yourself »

Note: NULL values are ignored.


Demo Database

Below is a selection from the "OrderDetails" table in the Northwind sample database: OrderDetailID OrderID ProductID Quantity 1 10248 11 12 2 10248 42 10 3 10248 72 5 4 10249 14 9 5 10249 51 40


SUM() Example

The following SQL statement finds the sum of the "Quantity" fields in the "OrderDetails" table:

ExampleSELECT SUM(Quantity)
FROM OrderDetails;Try it Yourself »

Note: NULL values are ignored.


Test Yourself With Exercises

Exercise:

Use the correct function to return the number of records that have the Price value set to 18.SELECT (*) FROM Products Price = 18;
Submit Answer »

Start the Exercise
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