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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