How to use ROW_NUMBER Function in SQL Server

Syntax of the ROW_NUMBER() function:

ROW_NUMBER() OVER (
    [PARTITION BY partition_expression, ... ]
    ORDER BY sort_expression [ASC | DESC], ...
)

For example:

SELECT ROW_NUMBER() OVER (ORDER BY FirstName) as Order, FirstName, LastName, City
FROM Customers

Result

The ROW_NUMBER() function is useful for pagination, It is a temporary value calculated when the query is run.