From: Tom Lane <tgl@sss.pgh.pa.us>
To: "David G. Johnston" <david.g.johnston@gmail.com>
cc: Wells Oliver <wells.oliver@gmail.com>,
        pgsql-admin <pgsql-admin@postgresql.org>
Subject: Re: Table column vales to JSON object keys?
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Comments: In-reply-to "David G. Johnston" <david.g.johnston@gmail.com>
	message dated "Thu, 11 Feb 2021 13:13:02 -0700"
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Date: Thu, 11 Feb 2021 15:15:35 -0500
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"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Thursday, February 11, 2021, Wells Oliver <wells.oliver@gmail.com> wrote:
>> Trying to go from a table like:
>> 
>> g  | e |  angle | path
>> ----+---+--------+----------------------
>> g1 | e1 | a1    | http://foo.com/a.mp4
>> g1 | e1 | a2    | http://foo.com/b.mp4
>> g1 | e1 | a3    | http://foo.com/c.mp4
>> 
>> To a table like this, with a column value per angle as a key.
>> 
>> g  | e |  obj
>> ----+---+---------------------------------------------------
>> ------------------------------------------
>> g1 | e1 | {"a1": "http://foo.com/a.mp4", "a2": "http://foo.com/b.mp4",
>> "a3": "http://foo.com/c.mp4"}
>> 
>> Can't quite get there.

> How far can you get?

I'm guessing something like

SELECT g, e, json_object_agg(angle, path) FROM ... GROUP BY g, e

would work, but haven't experimented.

			regards, tom lane