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Oracle Row Limit
ex: ID   EVENT EVENT_DESC
    __   _____ __________
    1723    1A    1A desc
    1723    1B    1B desc
    2214    2A    2A desc
    2214    2B    2B desc

SELECT *
FROM (
   SELECT id,
          event,
          event_desc,
          rank() over (order by id desc) as rnk
   FROM your_table
)
WHERE rnk <= 10

SELECT TOP 10 ID FROM TABLE
GROUP BY ID

SELECT ID FROM (
    SELECT DISTINCT ID FROM TABLE ORDER BY ID
)
WHERE rownum <= 10