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FIRST_ROWS(2) and ROWNUM in WHERE clause.

guruparanJun 5 2008 — edited Jun 5 2008

I am little bit curious when I wrote this post.

 SELECT *
   FROM emp
 WHERE ROWNUM < 2;

against

 SELECT /*+ FIRST_ROWS(1)*/ *
   FROM emp;

When I saw 'EXPLAIN_PLAN' there was huge difference and the second query was a lot better. I know that with the second query we are passing a hint to Optimizer.

But, let some one explain it more clearly?

Thanks in advance.

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Locked on Jul 3 2008

Added on Jun 5 2008

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