SQL COUNT() Function

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

SQL COUNT(column_name) Syntax

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

SQL COUNT(*) Syntax

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

SQL COUNT(DISTINCT column_name) Syntax

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

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

SQL COUNT(column_name) Example

We have the following "Purchases" table:

Now we want to count the number of Purchases from "Customer Tendulkar".

We use the following SQL statement:

The result of the SQL statement above will be 2, because the customer Tendulkar has made 2 Purchases in total:

SQL COUNT(*) Example

If we omit the WHERE clause, like this:

The result-set will look like this:

which is the total number of rows in the table.

SQL COUNT(DISTINCT column_name) Example

Now we want to count the number of unique customers in the "Purchases" table.

We use the following SQL statement:

The result-set will look like this:

which is the number of unique customers (Karmen, Tendulkar, and Jensen) in the "Purchases" table.