嘿,伙计们,我正在为考试做一些修改,并通过过去的论文,有人可以告诉我我是否走在正确的轨道上。
考虑下面给出的保险数据库:
person (driver-id, name, address)<br>
car (license, model, year)<br>
accident (report-number, date, location)<br>
owns (driver-id, license) <br>
participated (driver-id, car, report-number, damage-amount)<br>
1) 找出 2004 年发生事故的拥有汽车的总人数。
这是我想出的:
SELECT COUNT(driver-id)
FROM participated
WHERE participated.reportnumber=accident.reportnumber
AND accident.date = 2004
我在正确的轨道上吗?任何帮助,将不胜感激。