select - How to get records randomly from the oracle database?

Question

I need to select rows randomly from an Oracle DB.

Ex: Assume a table with 100 rows, how I can randomly return 20 of those records from the entire 100 rows.

Answer 1

SELECT *
FROM   (
    SELECT *
    FROM   table
    ORDER BY DBMS_RANDOM.RANDOM)
WHERE  rownum < 21;