Re: default value returned from sql stmt

Richard Huxton <dev@archonet.com>

From: Richard Huxton <dev@archonet.com>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: David Salisbury <salisbury@globe.gov>, pgsql-general@postgresql.org
Date: 2012-03-30T08:22:09Z
Lists: pgsql-general
On 30/03/12 08:46, Pavel Stehule wrote:
> 2012/3/30 Richard Huxton<dev@archonet.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