Re: CASE Statement - Order of expression processing

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От Albe Laurenz
Тема Re: CASE Statement - Order of expression processing
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Msg-id A737B7A37273E048B164557ADEF4A58B17BB3B00@ntex2010a.host.magwien.gv.at
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Ответ на Re: CASE Statement - Order of expression processing  (Andrea Lombardoni <andrea@lombardoni.ch>)
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Andrea Lombardoni wrote:
> It gets even stranger:
> 
> template1=# SELECT CASE WHEN (SELECT 0)=0 THEN 0 ELSE 1/(select 0) END;
>  case
> ------
>     0
> (1 row)
> 
> Here it seems that the ELSE does not get evaluated (which is correct).

Yes, of course, because both subselects will not get evaluated at
planning time.

The problem occurs only if one of the branches gets evaluated at plan time
but the condition doesn't.

Yours,
Laurenz Albe

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