1.交叉连接
select * from A ,B
2.内连接 可以省略inner join
隐式内连接：
select * from A,B where A.id = B.aid;
显式内连接：
select * from A inner join B on A.id = B.aid;
迫切内连接：
需要加上fetch关键字
内连接查询两者共有的属性数据。
3.外连接 outer join
左外连接：
select * from A left outer join B on A.id= B.aid;
右外连接：
select * from A right outer join B on A.id = B.aid;
迫切左外连接：需要加上fetch关键字，返回的是对象，不再是数组。
外连接查询共有属性和一方连接的属性
Session session = HibernateUtils.getCurrentSession();Transaction tx = session.beginTransaction();// SQL:SELECT * FROM cst_customer c INNER JOIN cst_linkman l ON// c.cust_id = l.lkm_cust_id;// HQL:内连接 from Customer c inner join c.linkMans/** List<Object[]> list = session.createQuery(* "from Customer c inner join c.linkMans").list(); for (Object[]* objects : list) { System.out.println(Arrays.toString(objects)); }*/// HQL:迫切内连接 其实就在普通的内连接inner join后添加一个关键字fetch. from Customer c inner// join fetch c.linkMansList<Customer> list = session.createQuery("select distinct c from Customer c inner join fetch c.linkMans").list();// 通知hibernate，将另一个对象的数据封装到该对象中for (Customer customer : list) {System.out.println(customer);}tx.commit();
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