DB2数据库必须掌握的常用语句：
1、 求每位客户订购的每种产品的总数量及平均单价，并按客户号，产品号从小到大排列
Select cust_id,prod_id,sum(qty),sum(qty*unit_price)/sum(qty)
From sales a, sale_item b
Where a.order_no=b.order_no
Group by cust_id,prod_id
Order by cust_id,prod_id
2、 查询订购了三种以上产品的订单号
Select order_no
from sale_item
Group by order_no
Having count(*)>3
3、 查询订购的产品至少包含了订单3号中所订购产品的订单
Select distinct order_no
From sale_item a
Where order_no<>'3'and not exists (
Select * from sale_item b where order_no ='3' and not exists
(select * from sale_item c where c.order_no=a.order_no and c.prod_id=b.prod_id))
4、 在sales表中查找出订单金额大于"E0013业务员在1996/11/10这天所接每一张订单的金额"的所有订单，并显示承接这些订单的业务员和该订单的金额
Select sale_id,tot_amt from sales
where tot_amt>all(select tot_amt
from sales
where sale_id='E0013' and order_date='1996-11-10')
5、 查询末承接业务的员工的信息
Select *
From employee a
Where not exists
(select * from sales b where a.emp_no=b.sale_id)
6、 查询来自上海市的客户的姓名，电话、订单号及订单金额
Select cust_name,tel_no,order_no,tot_amt
From customer a ,sales b
Where a.cust_id=b.cust_id and addr='上海市'
7、 查询每位业务员各个月的业绩，并按业务员编号、月份降序排序
Select sale_id,month(order_date), sum(tot_amt)
from sales
group by sale_id,month(order_date)
order by sale_id,month(order_date) desc
8、 求每种产品的总销售数量及总销售金额，要求显示出产品编号、产品名称，总数量及总金额，并按产品号从小到大排列
Select a.prod_id,prod_name,sum(qty),sum(qty*unit_price)
From sale_item a,product b
Where a.prod_id=b.prod_id
Group by a.prod_id,prod_name
Order by a.prod_id
9、 查询总订购金额超过'C0002'客户的总订购金额的客户号，客户名及其住址
Select cust_id, cust_name,addr
From customer
Where cust_id in (select cust_id from sales
Group by cust_id
Having sum(tot_amt)>
(Select sum(tot_amt) from sales where cust_id='C0002'))
10、 查询业绩***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)
11、 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
12、 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)
