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Re: performance question

From: Sybrand Bakker <sybrandb_at_hccnet.nl>
Date: Tue, 08 Feb 2005 21:44:30 +0100
Message-ID: <j19i01p9b64usksdvd6ebb3f90j8jtpk5e@4ax.com>


On Tue, 8 Feb 2005 21:02:19 +0100, "Jan van Veldhuizen" <jan_at_van-veldhuizen.nl> wrote:

>What will be better?
>
>UPDATE table1
>SET table1.some_col =
> (SELECT some_col FROM table2
> WHERE table2.col_id = table1.col_id)
>WHERE EXISTS
> (SELECT null FROM table2
> WHERE table2.col_id = table1.col_id)
>
>or:
>
>CREATE VIEW my_view AS SELECT table1.some_col c1, table2.some_col c2
> WHERE table1.col_id = table2.col_id
>
>UPDATE my_view SET c1 = c2
>
>

The view will be not updatable.

IIRC you'll need to
update
(select table1.some_col c1, table2.some_col c2  from table1, table2
where table1.col_id = table2.col_id)
set c1=c2

--
Sybrand Bakker, Senior Oracle DBA
Received on Tue Feb 08 2005 - 14:44:30 CST

Original text of this message

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