Re: Extracting data from jsonb array?

On Mon, Dec 7, 2020 at 7:12 PM Steve Baldwin <steve(dot)baldwin(at)gmail(dot)com>
wrote:

> How about this:
>
> b2bcreditonline=# select f.id, array_agg(t.key2) from foo as f,
> jsonb_to_recordset(js) as t(key2 text) group by f.id;
> id | array_agg
> ----+--------------------
> 2 | {r2k2val,r2k2val2}
> 1 | {r1k2val,r1k2val2}
> (2 rows)
>

Oh I like that, and thanks! It seems a little clearer to me, but maybe
that's because records still seem more familiar than json. Applying the
quantitative cumbersome-syntax test, this clocks in 8 characters shorter
than the other one (99 vs. 107). But this has a big advantage in that you
can just add other fields to the query, thusly:

=> select f.id, f.f1,f.f2,array_agg(t.key2) from foo as f,
jsonb_to_recordset(js) as t(key2 text) group by f.id;
id | f1 | f2 | array_agg
----+-----------+------------+--------------------
2 | My Text 2 | My Text 2a | {r2k2val,r2k2val2}
1 | My Text 1 | My Text 1a | {r1k2val,r1k2val2}
(2 rows)

That clocks in at 109 characters, compared to 178 for the similar query we
previously had:

SELECT id,f1,f2,array_agg AS vals FROM foo LEFT JOIN (select id,
array_agg(fa) from (select id, (jsonb_array_elements(js)->>'key') as fa
from foo) g group by id) foo2 USING (id);

Upgrade to v12+ for access to simpler/cleaner.

I can't upgrade just yet, but that is something to look forward to. Out of
curiosity, what would an equivalent query look like in V12?

Cheers,
Ken

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