Re: Syntax error needs explanation

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