Re: Where the info is stored

From: Igor Korot <ikorot01(at)gmail(dot)com>
To: "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>
Cc: "pgsql-generallists(dot)postgresql(dot)org" <pgsql-general(at)lists(dot)postgresql(dot)org>
Subject: Re: Where the info is stored
Date: 2026-03-01 05:34:58
Message-ID: CA+FnnTwaK-Z26KeqoPsAkKPJHo9OjMJdSse8tXE-KSFV9y0g_Q@mail.gmail.com
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Hi, David,

On Sat, Feb 28, 2026 at 7:42 PM David G. Johnston
<david(dot)g(dot)johnston(at)gmail(dot)com> wrote:
>
> On Sat, Feb 28, 2026 at 6:34 PM Igor Korot <ikorot01(at)gmail(dot)com> wrote:
>>
>> And why there is no WHERE populated?
>>
>> Thank you.
>>
>> On Sat, Feb 28, 2026 at 7:05 PM Igor Korot <ikorot01(at)gmail(dot)com> wrote:
>> >
>> > Hi, David,
>> >
>> > On Sat, Feb 28, 2026 at 7:02 PM David G. Johnston
>> > <david(dot)g(dot)johnston(at)gmail(dot)com> wrote:
>> > >
>> > > On Saturday, February 28, 2026, Igor Korot <ikorot01(at)gmail(dot)com> wrote:
>> > >>
>> > >> FROM pg_constraint co, pg_namespace n, pg_class
>> > >>
>> > >> As you can see only the constraint name and the tablespace are
>> > >> populated correctly.
>> > >
>> > >
>> > > Constraints don’t have included columns. Only indexes do. You need to query the index, not the constraint.
>> >
>> > I literally copied your query into my code and it didn't populated
>> > anything...
>> >
>> > Am I missing something?
>>
>
> I trimmed your query to emphasize/point-out that you were querying pg_constraint and that doing so to find included columns is doomed to failure (I suppose it could have been used to find the index, but in this case it wasn't. I haven't explored that approach.). You should step back and consider why you thought the fragment I included in my reply, a bare FROM clause, would somehow be executable since it is in no way a valid query.

draft=# WITH idx AS( SELECT i.indexrelid, i.indrelid, i.indnkeyatts,
i.indkey::int2[] AS indkey FROM pg_index i, pg_class ic, pg_namespace
ns WHERE ic.oid = i.indexrelid AND ns.oid = ic.relnamespace AND
ns.nspname = 'public' AND ic.relname = 'leagues_new' ), ords AS (
SELECT idx.indexrelid, idx.indrelid, idx.indnkeyatts, s.ord,
idx.indkey[s.ord] AS attnum FROM idx CROSS JOIN LATERAL
generate_subscripts(idx.indkey, 1) AS s(ord) ) SELECT ns.nspname,
ic.relname, tc.relname, a.attname, CASE WHEN ords.ord <
ords.indnkeyatts THEN 'key' ELSE 'include' END, ords.ord + 1 AS
index_position FROM pg_attribute a, ords, pg_class ic, pg_namespace
ns, pg_class tc WHERE a.attrelid = ords.indrelid AND a.attnum =
ords.attnum AND NOT a.attisdropped AND ic.oid = ords.indexrelid AND
ns.oid = ic.relnamespace AND tc.oid = ords.indrelid AND ords.ord >
ords.indnkeyatts;
nspname | relname | relname | attname | case | index_position
---------+---------+---------+---------+------+----------------
(0 rows)

draft=#

This is an exact replica of your query from the first post where you put it.

I only removed AS statements.

As you can see 0 rows are returned.

Thank you.

>
> David J.
>

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