Re: [PATCH] Proposal for HIDDEN/INVISIBLE column - Mailing list pgsql-hackers

From Isaac Morland
Subject Re: [PATCH] Proposal for HIDDEN/INVISIBLE column
Date
Msg-id CAMsGm5dt-hmm_LKGu=Taecb+RHEeKrh=Ss7gr2+3C__w_ywoUw@mail.gmail.com
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In response to Re: [PATCH] Proposal for HIDDEN/INVISIBLE column  (Gilles Darold <gilles@migops.com>)
Responses Re: [PATCH] Proposal for HIDDEN/INVISIBLE column
List pgsql-hackers
On Sun, 17 Oct 2021 at 17:42, Gilles Darold <gilles@migops.com> wrote:
 
Yes, my first though was to allow all columns to be unexpandable like a
table without column, but the the problem is that when you execute
"SELECT * FROM nada" it returns no rows which is not the case of a table
with hidden column. I could fix that to return no rows if all columns
are unexpandable but I think that all column hidden is a nonsens so I
have prefered to not allow it and an error is raised.

Perhaps I misunderstand what you are saying, but a no-columns table definitely can return rows:

psql (12.2)
Type "help" for help.

postgres=# create table nada ();
CREATE TABLE
postgres=# insert into nada default values;
INSERT 0 1
postgres=# insert into nada default values;
INSERT 0 1
postgres=# table nada;
--
(2 rows)

postgres=#

Note that psql doesn't display a separate line for each row in this case, but the actual result coming back from the server does contain the appropriate number of rows. 

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