Re: Converting row elements into a arrays?

From: Rob Sargent <robjsargent(at)gmail(dot)com>
To: pgsql-general(at)lists(dot)postgresql(dot)org
Subject: Re: Converting row elements into a arrays?
Date: 2023-03-02 21:45:49
Message-ID: e994b049-93f1-d739-e74c-ecd29bbbe4c5@gmail.com
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On 3/2/23 13:58, Ron wrote:
> Postgresql 12.13
>
> Given the sample below, I'm looking for how to generate this output. 
> It's like GROUP BY, but generating an array instead of an aggreate
> number.
>  f1 | f2_array
> ----+---------
> 1 | {1,2,3}
>   2 | {1,2,3,4}
>   3 | {1,2}
>
> The ultimate goal is to somehow use pg_index.indkey to get column
> names from pg_attribute.
>
> create table foo (f1 int, f2 int);
> insert into foo values (1, 1);
> insert into foo values (1, 2);
> insert into foo values (1, 3);
> insert into foo values (2, 1);
> insert into foo values (2, 2);
> insert into foo values (2, 3);
> insert into foo values (2, 4);
> insert into foo values (3, 1);
> insert into foo values (3, 2);
>
> select * from foo order by f1, f2;
>  f1 | f2
> ----+----
>   1 |  1
>   1 |  2
>   1 |  3
>   2 |  1
>   2 |  2
>   2 |  3
>   2 |  4
>   3 |  1
>   3 |  2
> (9 rows)
>

In which environment are you accessing that array?  psql only?

>
>

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