Oracle ROW_NUMBER Function: Guide & Usage

The ROW_NUMBER function is a window function in Oracle database that assigns a unique consecutive number to each row in a query result set. Its syntax is as follows:

Generate a sequential number for each row based on the specified order of multiple columns.

In this case, ROW_NUMBER is the name of a function, parameters are not required within the parentheses, the OVER clause specifies the scope of the analytic function, and the ORDER BY clause is used to define the sorting order of the rows and can have multiple sorting criteria specified.

The ROW_NUMBER function can easily assign numbering to the rows in a result set, such as for implementing pagination or sorting the query results.

Here is an example demonstrating how to use the ROW_NUMBER function:

Get the row number, employee ID, first name, last name, and salary of employees in department 50, ordered by salary in descending order.

In the example above, we sorted the employees in the department with the ID of 50 in descending order based on their salary, and assigned a unique consecutive number to each row, which was stored in the column row_num.

Please note that the ROW_NUMBER function simply assigns a unique number to each row and does not perform any actual calculations or aggregations. If you need to perform calculations or aggregations on rows, you can use other window functions such as SUM, AVG, COUNT, etc.