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Re: UNION ALL and ordering

From: Ravip via DBMonster.com <u36659_at_uwe>
Date: Fri, 23 Nov 2007 14:52:20 GMT
Message-ID: <7ba5aa48273ca@uwe>


By default the output will be result of first select and then second select.

chrism778_at_gmail.com wrote:
>When I UNION ALL two sql statements, I need the results from the first
>statement to come back first in the result set. So if I do something
>like:
>
>select col1, col2, ... from table1 order by col2
>UNION ALL
>select col1, col2, ... from table2 order by col3
>
>can I always assume that the results will come back with table1 rows
>first followed by the table2 results? From some limited testing, this
>appears to be the case, but is Oracle designed to work this way, or
>have I just been lucky?
>
>If this isn't the case, then I would have to add a pseudo column and
>sort by it like this:
>
>select 1, col1, col2, ... from table1 order by col2
>UNION ALL
>select 2, col1, col2, ... from table2 order by col3
>ORDER BY 1
>
>The problem with this approach, is that any order bys I do in the
>individual select statements may no longer be valid because of the
>"ORDER BY 1" for the UNION.

-- 
Message posted via http://www.dbmonster.com
Received on Fri Nov 23 2007 - 08:52:20 CST

Original text of this message

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