Re: default value returned from sql stmt

From: Richard Huxton <dev(at)archonet(dot)com>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: David Salisbury <salisbury(at)globe(dot)gov>, pgsql-general(at)postgresql(dot)org
Subject: Re: default value returned from sql stmt
Date: 2012-03-30 08:22:09
Message-ID: 4F756D31.2050009@archonet.com
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On 30/03/12 08:46, Pavel Stehule wrote:
> 2012/3/30 Richard Huxton<dev(at)archonet(dot)com>:
>> On 29/03/12 23:28, Pavel Stehule wrote:
>>>
>>> select anum from t1 where anum = 4
>>> union all select 100 limit 1;
>>
>>
>> I'm not sure the ordering here is guaranteed by the standard though, is it?
>> You could end up with the 4 being discarded.
>
> A order is random for only "UNION", "UNION ALL" should to respect
> order. But I didn't check it in standard.

Let's put it this way - a quick bit of googling can't find anything that
says the order *is* guaranteed, and (almost?) no other operations do so
by default.

--
Richard Huxton
Archonet Ltd

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