Re: is any reason why only one columns subselect are allowed in array()?

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От Pavel Stehule
Тема Re: is any reason why only one columns subselect are allowed in array()?
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Msg-id 162867790811181013t20532dcai7bbb399edb1aad7e@mail.gmail.com
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Ответ на Re: is any reason why only one columns subselect are allowed in array()?  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: is any reason why only one columns subselect are allowed in array()?  (Tom Lane <tgl@sss.pgh.pa.us>)
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2008/11/18 Tom Lane <tgl@sss.pgh.pa.us>:
> Sam Mason <sam@samason.me.uk> writes:
>> I've used this syntax before and got a surprising message back.  I'd
>> expect to be able to do the following:
>>
>> and get the following back {"(a,1)","(b,2)"}.  So I think I'm with
>> David.
>
> I concur --- if we support something like this, the behavior should be
> that you get an array of record.  Pavel's proposal for a 2-D array seems
> unworkably restrictive.  And I certainly don't want to end up in a
> situation where we return either a 2-D array or array of record
> depending on whether the parser thinks the column data types match ...

there are clean rules. you do array from input - when input is 1D
array, then result is 2D array, when input is record, then result is
1D array of record. Where should be problem? I see Sam proposal as
only one special case of my proposal.

Pavel

I am sorry, but you know - record type is very unfriendly to plpgsql.

>
>                        regards, tom lane
>
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