MySQL--分组数据

1 #连接数据库
2 use newschema;
3 #查看表中数据
4 select *from products；
5 #返回供应商1003提供的产品数目
6 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;