Date: Mon, 14 Jul 2025 12:59:02 -0700 (PDT)
From: Rich Shepard <rshepard@appl-ecosys.com>
To: pgsql-general <pgsql-general@postgresql.org>
Subject: Re: Syntax error needs explanation
In-Reply-To: <ce828b41-3e25-4f68-aed2-397fddff8849@aklaver.com>
Message-ID: <6684eaa7-e6e2-a45b-cff9-44597ca3c8ad@appl-ecosys.com>
References: <9c84776d-d938-9fa4-ab1-6ee960ce6e7d@appl-ecosys.com> <7ec33517-6dc1-4e1d-b741-0c26eba7cc79@aklaver.com> <bb74e92e-1cf-1f7e-eeaa-44ce4162f7fd@appl-ecosys.com> <ce828b41-3e25-4f68-aed2-397fddff8849@aklaver.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII; format=flowed
Archived-At: <https://www.postgresql.org/message-id/6684eaa7-e6e2-a45b-cff9-44597ca3c8ad%40appl-ecosys.com>
Precedence: bulk

On Mon, 14 Jul 2025, Adrian Klaver wrote:

> That does not matter, that is more for user convenience in figuring out what 
> the files are for.

Adrian,

Okay.

I still have issues with the script. I want a count of companies with
regulatory enforcement actions by industry. Since not all regulated
companies have had such actions I want only those with rows in the
enforcemewnt table and haven't before used the EXISTS operator and a
subquery.

The current version of the script:

select c.company_nbr, c.company_name, c.industry
from companies as c
where exists (
   select e.company_nbr
   from enforcement as e
   )
group by c.industry
order by c.industry;

And psql tells me that c.company_nbr must be in the group by clause.
However, when I do that the output is a list of company numbers and names in
each industry.

My web searches on using the exists operator haven't provided the knowlege
for me to use it properly.

Rich