SQL COUNT() Function
The SQL COUNT() Function
The COUNT() function returns the number of
rows that matches a specified criterion.
Example
Find the total number of rows in the Products
table:
FROM Products;
Syntax
SELECT COUNT(column_name)
FROM table_name
WHERE condition;
Demo Database
Below is a selection from the Products table used in the examples:
| 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 |
Specify Column
You can specify a column name instead of the asterix symbol (*).
If you specify a column name instead of (*), NULL values will not be counted.
Example
Find the number of products where the ProductName is not null:
FROM Products;
Add a WHERE Clause
You can add a WHERE clause to specify conditions:
Example
Find the number of products where Price is higher than 20:
FROM Products
WHERE Price > 20;
Ignore Duplicates
You can ignore duplicates by using the DISTINCT keyword in the
COUNT() function.
If DISTINCT is specified, rows with the same value for the specified column will be counted as one.
Example
How many different prices are there in the Products table:
FROM Products;
Use an Alias
Give the counted column a name by using the AS keyword.
Example
Name the column "Number of records":
FROM Products;
Use COUNT() with GROUP BY
Here we use the COUNT() function and the
GROUP BY clause, to return the number of
records
for each category in the Products table:
Example
FROM Products
GROUP BY CategoryID;
You will learn more about the
GROUP BY clause later in this tutorial.