MySQL数据分组

创建分组

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

过滤分组：过滤两个以上订单的分组

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

过滤具有2个（含）以上产品、价格为10（含）以上的供应商

select vend_id, count(*) as num_prods 
from products  
where prod_price >= 10 
group by vend_id 
having count(*)>= 2;            

分组和排序：检索总计订单价格大于等于50的订单的订单号和总计订单价格，按总计订单价格排序输出

select order_num, sum(quantity*item_price) as ordertotal 
from orderitems 
group by order_num 
having sum(quantity*item_price) >=50 
order by ordertotal;