consider the relation
person(driver_id,name,address)
car(license,model,year)
accident(report_number,date,location)
own(driver_id,license)
participated(report_number,license,driver_id,damage_amount)
query=find the total number of people who owned the car that were involved in accident in 2009.
my answer is
select count(driver_id),report number
from (car natural join own)natural join(accident natural join participated)
where date=2009.
group by report number
am i right???