COUNT() Function

The COUNT() function counts the number of rows that meet specific criteria in a dataset. It is versatile and can be used in different forms: COUNT(*) counts all rows, including NULLs, while COUNT(column_name) counts only non-NULL values. The syntax is as follows: SELECT COUNT(*) FROM table_name WHERE condition;. For instance, to count the total number of employees, you might execute: SELECT COUNT(employee_id) FROM employees;. This function is crucial for generating metrics and statistics, such as total transactions, active users, or product inventories. It helps organizations track performance and assess operational efficiency. By combining COUNT() with GROUP BY, you can summarize counts by categories, such as counting employees in each department or products sold by each sales representative.