Mysql基础第十八天,链接表

Posted 2021-08-06 2019ab

关系表

 select p.prod_id,prod_name,p.vend_id,v.vend_name from products p join
  vendors v on p.vend_id = v.vend_id;  // 默认内连接 

创建连接

select p.prod_id,prod_name,p.vend_id,v.vend_name from products p left join
  vendors v on p.vend_id = v.vend_id;  
select p.prod_id,prod_name,p.vend_id,v.vend_name from products p right join
  vendors v on p.vend_id = v.vend_id;