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Oracle9i SQL Reference
Release 2 (9.2)

Part Number A96540-02
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Text description of functions58.gif follows
Text description of row_number

See Also:

"Analytic Functions" for information on syntax, semantics, and restrictions


ROW_NUMBER is an analytic function. It assigns a unique number to each row to which it is applied (either each row in the partition or each row returned by the query), in the ordered sequence of rows specified in the order_by_clause, beginning with 1.

You cannot use ROW_NUMBER or any other analytic function for expr. That is, you can use other built-in function expressions for expr, but you cannot nest analytic functions.

See Also:

"About SQL Expressions" for information on valid forms of expr


For each department in the sample table oe.employees, the following example assigns numbers to each row in order of employee's hire date:

SELECT department_id, last_name, employee_id, ROW_NUMBER()
   OVER (PARTITION BY department_id ORDER BY employee_id) AS emp_id
   FROM employees;

------------- ------------------------- ----------- ----------
           10 Whalen                            200          1
           20 Hartstein                         201          1
           20 Fay                               202          2
           30 Raphaely                          114          1
           30 Khoo                              115          2
           30 Baida                             116          3
           30 Tobias                            117          4
           30 Himuro                            118          5
           30 Colmenares                        119          6
           40 Mavris                            203          1
          100 Popp                              113          6
          110 Higgins                           205          1
          110 Gietz                             206          2

ROW_NUMBER is a nondeterministic function. However, employee_id is a unique key, so the results of this application of the function are deterministic.

See Also:

FIRST_VALUE and LAST_VALUE for examples of nondeterministic behavior