You can use the script below to see how many systems are being monitored by each company
select b.alarm_company_code as "Alarm Company",
b.inactive as "Alarm Company Code Inactive Y/N", --b.alarm_company_id,
count(a.alarm_company_id) as "Number of Systems with Alarm Company Code", b.description
from ar_customer_system a, cs_alarm_company b
where a.alarm_company_id=b.alarm_company_id and a.Customer_Id > 1
group by b.alarm_company_code, b.inactive, a.alarm_company_id, b.alarm_company_id, b.description
order by b.alarm_company_code