What is the purpose of the MySQL row_number() function?

11 months ago

William Carter

1 minute

In MySQL, the ROW_NUMBER() function is used to assign a unique number to each row in the query result set. It is often used in conjunction with the OVER() clause, which defines the columns to be sorted and the order of sorting.

The purpose of the ROW_NUMBER() function is to assign a unique integer value to each row, which is sorted according to the specified order. This number can be used for paging the results, removing duplicate data, or performing other specific operations.

Here is an example using the ROW_NUMBER() function:

SELECT ROW_NUMBER() OVER(ORDER BY column_name) AS row_num, column_name
FROM table_name;

This example utilizes the ROW_NUMBER() function to assign a sequential number to each row in the query result set, sorted by the values in the column_name column. The statement AS row_num names the assigned number as row_num for display in the result set.

Note: The ROW_NUMBER() function is not directly available in MySQL, but a similar functionality can be achieved using other methods such as variables or self-joins.