(1)所有售货员都出售过的商品名称

select pname
from p,r
where p.pno=r.pno and num>o

(2)每个销售人员的总计销售金额

select sno,price*num as 总销售额
from p,s,r
where s.sno=r.sno and p.pno=r.pno

学生可以吗？
我是大二学生！

select pname
      from  p
      where p.pno =r.pno (select sneme
                           from  r
                           where num>0)
                     
                  我不知道对不对！！！~~~

(1)select PNAME from P,R where P.PNO=R.PNO and (select count(*) from R group by PNO)=(select count(*) from S)

(2)select PNAME,sum(PRICE*NUM) as 总额 from P,S,R where R.SNO=S.SNO and R.PNO=P.PNO group by S.SNO