SQL question

From: Ramadoss, Karthik <Karthik.Ramadoss_at_accidentfund.com>
Date: Wed, 24 Oct 2012 19:00:45 +0000
Message-ID: <92583F1E24E0E94485E321E139D18321B42CFE25_at_Stromboli.accidentfund.com>

This is probably a simple one but definitely something new for me. Database: 11.2.0.3
OS: Oracle Linux 5.6

A SQL like

              SELECT A.COL1,
                     A.COL2,
                     B.COL3
                FROM TABLE1 A,
                     TABLE2 B,
                     TABLE3 C
               WHERE A.ID = B.ID AND B.ID = C.ID

returns 1,192,940 rows.

And

        SELECT COUNT(*) from
      (SELECT A.COL1,
                     A.COL2,
                     B.COL3
                FROM TABLE1 A,
                     TABLE2 B,
                     TABLE3 C
               WHERE A.ID = B.ID AND B.ID = C.ID)

Returns 1,192,978 rows.

Anyone know what is going on here? I would expect both to return the same number of rows.

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Received on Wed Oct 24 2012 - 21:00:45 CEST