#连接数据库

 use newschema;

 #查看表中数据

 select *from products；

 #返回供应商1003提供的产品数目

 select count(*) as num_prods from products where vend_id=1003;

select vend_id,count(*) as num_prods from products group by vend_id;

#使用with rollup

select vend_id,count(*) as num_prods from products group by vend_id with rollup;

#使用with rollup关键字，可以得到每个分组以及每个分组汇总级别（针对每个分组）的值。

select cust_id,count(*) as orders from orders group by cust_id having count(*)>=2;

select vend_id,count(*) as num_prods

from products

where prod_price>=10

group by vend_id

having count(*)>=2;

select vend_id,count(*) as num_prods

 from products

group by vend_id

having count(*)>=2;

select order_num,sum(quantity*item_price) as ordertotal

from orderitems

group by order_num

having sum(quantity*item_price)>=50;

select order_num,sum(quantity*item_price) as ordertotal

from orderitems

group by order_num

having sum(quantity*item_price)>=50

order by ordertotal;