RE: OR Vs UNION

From: Jamadagni, Rajendra <Rajendra.Jamadagni_at_espn.com>
Date: Tue, 24 Jun 2003 07:25:49 -0700
Message-ID: <F001.005B866E.20030624070953@fatcity.com>

I believe OR is internally transformed to UNION (or UNION ALL) ??

The answer you are looking is ... test and measure it in _your_ _environment_.

Raj

---

Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !

>----- ------- Original Message ------- -----
>From: [EMAIL PROTECTED]
>To: Multiple recipients of list ORACLE-L
><[EMAIL PROTECTED]>
>Sent: Mon, 23 Jun 2003 21:34:52
>
>
>
>
>
>Hi All,
>
>Could someone explain to me which one is best in
>the following two queries
>w.r.t performance?
>
>Thanks
>Sami
>
>Query1)
>========
>select distinct empployee_id from employees where
>department_id=10 or
>department_id=20
>/
>
>Query2)
>=======
>select employee_id from employees where
>department_id=10
>union
>select employee_id from employees where
>department_id=20
>/
>

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Received on Tue Jun 24 2003 - 09:25:49 CDT