ROW_NUMBER() Function

The ROW_NUMBER() function assigns a unique sequential integer to each row within the result set, starting from 1. Unlike RANK() or DENSE_RANK(), which may assign the same rank to tied values, ROW_NUMBER() always generates a unique value. This makes it particularly useful for scenarios requiring unique identifiers for each row. For example:

sqlCopy codeSELECT employee_id, salary, ROW_NUMBER() OVER (ORDER BY salary DESC) AS row_num FROM employees;

This query assigns a unique row number to each employee based on their salary, allowing for easy identification and manipulation of rows. The use of ROW_NUMBER() is especially helpful in pagination scenarios, where you might need to display a specific range of results, such as the top 10 employees by salary.