52、 查询业绩最好的的业务员号、业务员名及其总销售金额
select emp_no,emp_name,sum(tot_amt)
from employee a,sales b
where a.emp_no=b.sale_id
group by emp_no,emp_name
having sum(tot_amt)=
(select max(totamt)
from (select sale_id,sum(tot_amt) totamt
from sales
group by sale_id) c)
53、 查询每位客户所订购的每种产品的详细清单，要求显示出客户号，客户名，产品号，产品名，数量及单价
select a.cust_id, cust_name,c.prod_id,prod_name,qty, unit_price
from customer a,sales b, sale_item c ,product d
where a.cust_id=b.cust_id and b.order_no=c.order_no and c.prod_id=d.prod_id
54、 求各部门的平均薪水，要求按平均薪水从小到大排序
select dept,avg(salary)
from employee
group by dept
order by avg(salary)