My stuff

If you want to select random rows from a table, you can order the rows using the dbms_random.value function :

  SELECT COLUMN
    FROM TABLE
   ORDER BY dbms_random.VALUE

To get 20 random rows from the table, we can add a condition on rownum. This selects the first 20 rows :

  SELECT COLUMN
    FROM ( SELECT COLUMN
                 FROM TABLE
                ORDER BY dbms_random.VALUE )
   WHERE rownum < 21

With thanks to this site.