Examples of the COUNT(*) Function

In the following example, the user wants to know the total number of rows in the orders table. So the user calls the COUNT(*) function in a SELECT statement without a WHERE clause:

SELECT COUNT(*) AS total_rows FROM orders;

The following table shows the result of this query.

In the following example, the user wants to know how many rows in the orders table have a NULL value in the ship_instruct column. The user calls the COUNT(*) function in a SELECT statement with a WHERE clause, and specifies the IS NULL condition in the WHERE clause:

SELECT COUNT (*) AS no_ship_instruct FROM orders
   WHERE ship_instruct IS NULL;

The following table shows the result of this query.

In the following example, the user wants to know how many rows in the orders table have the value express in the ship_instruct column. So the user calls the COUNT(*) function in the projection list and specifies the equals ( = ) relational operator in the WHERE clause.

SELECT COUNT (*) AS ship_express FROM ORDERS
   WHERE ship_instruct = 'express';

The following table shows the result of this query.