SQL COUNT() Function

by Anuj Kumar

The SQL COUNT() function is used to count the number of rows in a result set or the number of occurrences of a particular condition in a table. It is often used in conjunction with the SELECT statement to retrieve information about the number of rows that meet a specified condition.

The basic syntax of the COUNT() function is as follows:

SELECT COUNT(column_name) FROM table_name WHERE condition;

column_name: The column for which you want to count the number of non-null values. You can also use * to count all rows regardless of a specific column.
table_name: The name of the table from which you want to retrieve the data.
condition: An optional condition that specifies which rows to count. If omitted, COUNT() will count all rows.

Here are a couple of examples:

Counting all rows in a table:

SELECT COUNT(*) FROM employees;

Counting the number of employees with a specific job title:

SELECT COUNT(*) FROM employees WHERE job_title = 'Manager';

Counting Distinct Values:

SELECT COUNT(DISTINCT department) FROM employees;

This query counts the number of distinct departments in the “employees” table.

Counting Rows Grouped by a Column:

SELECT department, COUNT(*) FROM employees GROUP BY department;

This query counts the number of employees in each department.

Counting Rows Using Aliases:

SELECT COUNT(*) AS total_employees FROM employees;

This query uses an alias (total_employees) for the result of the COUNT() function.

SQL COUNT() Function

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