Re: Expression to construct a anonymous record with named columns?

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От Benedikt Grundmann
Тема Re: Expression to construct a anonymous record with named columns?
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Msg-id CAMr3DCMJz=4d8eH2FK1qg4-+uZ7AZAFiCpXMmF66j30-X=16fw@mail.gmail.com
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Ответ на Re: Expression to construct a anonymous record with named columns?  (Alban Hertroys <haramrae@gmail.com>)
Ответы Re: Expression to construct a anonymous record with named columns?
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On 21 September 2012 07:50, Alban Hertroys <haramrae@gmail.com> wrote:
On 20 Sep 2012, at 20:36, Benedikt Grundmann wrote:

> So named anonymous records / row types seem to be strangely second class.  Can somebody clarify the restrictions and rationale or even better show a way to do the equivalent of (made up syntax ahead):
>
> select row(1 as a, 2 as b);

select * from (values (1, 2, 3)) a (a, b, c);

Thank you very much.  This is very interesting. However this again seems to be strangely limited, because I can neither extract a column from row that was constructed this way in a scalar position nor expand it:

proddb_testing=# select (select x from (values (1, 2, 3)) x (a, b, c));
 ?column? 
----------
 (1,2,3)
(1 row)

proddb_testing=# select (select x from (values (1, 2, 3)) x (a, b, c)).*;
ERROR:  syntax error at or near "."
LINE 1: select (select x from (values (1, 2, 3)) x (a, b, c)).*;
                                                             ^
proddb_testing=# select (select x from (values (1, 2, 3)) x (a, b, c)).a;
ERROR:  syntax error at or near "."
LINE 1: select (select x from (values (1, 2, 3)) x (a, b, c)).a;

 Any more insights?

Thanks,

bene

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