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;
