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.

total_rows
23

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.

no_ship_instruct
2

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.

ship_express
6