MySQL视图

利用视图简化复杂的联结

create view productcustomers as 
select cust_name, cust_contact,prod_id 
from customers, orders, orderitems 
where customers.cust_id = orders.cust_id 
and orderitems.order_num =orders.order_num;

select cust_name,cust_contact
from productcustomers
where prod_id = 'TNT2';

用视图重新格式化检索出的数据

create view vendorlocations as
select concat (rtrim(vend_name), ' (', rtrim(vend_country),')') as vend_title 
from vendors 
order by vend_name;

select *
from vendorlocations;

通过视图过滤数据

create view customeremaillists as
select cust_id,cust_name,cust_email
from customers
where cust_email is not null;

select *
from customeremaillists;

使用视图与计算字段

create view orderitemsexpand as
select prod_id, quantity, item_price, quantity*item_price as expanded_price 
from orderitems;

select *
from orderitemsexpand
where order_num = 20005;