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Re: sequence of numbers

From: Jan Pruner <jan_at_pruner.cz>
Date: Mon, 19 Nov 2001 05:19:18 -0800
Message-ID: <F001.003C85FA.20011119042519@fatcity.com>

select MIN(a.mt1)+1 INTO XY FROM
(select mt1 FROM MT MINUS SELECT mt1-1 FROM MT) a;

is better, but still full scan ...

JP

On Mon 19. November 2001 12:40, you wrote:
> Hello,
> I've a table mt ( mt1 NUMBER(10) NOT NULL ) with unique index on the mt1
> column.
> There's a sequence of numbers 1,2,3,4,6,7,8,10,11 ... in the mt1
>
> Now, I want to get the smallest number which is not in mt1
> (excluding min(mt1)-x of course) into XY (in my example is it n. 5).
>
> When I use SELECT MIN(mt1)-1 INTO XY FROM MT WHERE MT1 NOT IN (select
> mt1+1 from mt)
> my perfromance goes pretty down :-))) (there's about 5 mil. of numbers).
>
> Some idea how to get it without cursor?
>
> Thanks (and sorry it's monday)
> JP

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Author: Jan Pruner
  INET: jan_at_pruner.cz

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Received on Mon Nov 19 2001 - 07:19:18 CST

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