SQL COUNT() Function

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

The COUNT(column_name) function returns the number of values (NULL values will not be counted) of the specified column:

SELECT COUNT(column_name) FROM table_name;

The COUNT(*) function returns the number of records in a table:

SELECT COUNT(*) FROM table_name;

The COUNT(DISTINCT column_name) function returns the number of distinct values of the specified column:

SELECT COUNT(DISTINCT column_name) FROM table_name;

Note: COUNT(DISTINCT) works with ORACLE and Microsoft SQL Server, but not with Microsoft Access.

Demo Database

In this tutorial we will use the well-known Northwind sample database.

Below is a selection from the "Orders" table:

OrderID	CustomerID	EmployeeID	OrderDate	ShipperID
10265	7	2	1996-07-25	1
10266	87	3	1996-07-26	3
10267	25	4	1996-07-29	1

The following SQL statement counts the number of orders from "CustomerID"=7 from the "Orders" table:

SELECT COUNT(CustomerID) AS OrdersFromCustomerID7 FROM Orders
WHERE CustomerID=7;

The following SQL statement counts the total number of orders in the "Orders" table:

SELECT COUNT(*) AS NumberOfOrders FROM Orders;

The following SQL statement counts the number of unique customers in the "Orders" table:

SELECT COUNT(DISTINCT CustomerID) AS NumberOfCustomers FROM Orders;