Re: SELECT MAX(c) FROM (SELECT ... FOR UPDATE) AS foo

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От Jean-Luc Lachance
Тема Re: SELECT MAX(c) FROM (SELECT ... FOR UPDATE) AS foo
Дата
Msg-id 41221580.7070907@sympatico.ca
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Ответ на SELECT MAX(c) FROM (SELECT ... FOR UPDATE) AS foo  (Markus Bertheau <twanger@bluetwanger.de>)
Ответы Re: SELECT MAX(c) FROM (SELECT ... FOR UPDATE) AS foo  (Markus Bertheau <twanger@bluetwanger.de>)
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This query does not make sense to me.
Why would you create an updatable subquery just to get the highest value?

Maybe you are trying to achieve something other than what the query 
suggest. You wou care to put in words what you want to do?


JLL


Markus Bertheau wrote:

> Hi,
> 
> why is the following query not allowed:
> 
> SELECT MAX(position) FROM (SELECT position FROM classes WHERE name =
> 'foo' FOR UPDATE OF classes) AS foo
> 
> It's clear which rows should be locked here, I think.
> 
> Thanks
> 



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