Re: Syntax error needs explanation [RESOLVED]

[Rich Shepard]

On Mon, 14 Jul 2025, David G. Johnston wrote:

Yeah, you need both to read up on aggregate queries and correlated
subqueries which is typically how one makes uses of exists (it's called a
semi-join in this formulation)

David,

Thanks. I wasn't sure what to read.

Not tested, but:

select c.industry, count(*)
from companies as c
where exists (
select from enforcement as e
where e.company_nbr = c.company_nbr
)
group by c.industry;

Works as intended.

Many thanks,

Rich