SQL COUNT Function

The SQL COUNT() function is an aggregate function used to count the number of rows in a result set or the number of non-NULL values in a column. It is commonly used to determine the number of records that meet certain criteria.

COUNT() Function

The COUNT() function can be used in different ways, depending on what you need to count:

-- Count all rows in a table
SELECT COUNT(*) AS TotalRows
FROM table_name;

-- Count non-NULL values in a specific column
SELECT COUNT(column_name) AS NonNullValues
FROM table_name
WHERE condition;

        

Syntax

The basic syntax for using the COUNT() function is:

SELECT COUNT(expression) AS Alias
FROM table_name
WHERE condition;

        

Examples

Here are some examples of using the COUNT() function:

-- Count the total number of employees
SELECT COUNT(*) AS TotalEmployees
FROM Employees;

-- Count the number of employees with a specific job title
SELECT COUNT(JobTitle) AS NumberOfManagers
FROM Employees
WHERE JobTitle = 'Manager';

-- Count the number of orders placed by a customer
SELECT COUNT(OrderID) AS OrdersCount
FROM Orders
WHERE CustomerID = 'ALFKI';