Hibernate criteriaQuery - 左连接

如何使用条件查询来应用左连接，我只能在Internet上查找内连接条件。Hibernate criteriaQuery - 左连接

 Criteria cr = this.sessionFactory.getCurrentSession().createCriteria(A.class, "a").createAlias("a.division", "division");     
     List<A> list = cr.list();

除法是一个存在于A类中的实体，这是返回我的内部连接结果。我想申请左连接上划分实体：

select * from A as a left join divisions as division on division.id = a.id;

表的数据：

id name  division_id 
    1 first name 1 
    3 sec name 2 
    6 fourth name 2 
    5 3rd name NULL

表分割后的数据：

id type 
    1 F 
    2 G

内连接：

select * from A as a inner join division where a.division_id = division.id

内加入的结果：

+----+-------------+-------------+----+------+ 
| id | name  | division_id | id | type | 
+----+-------------+-------------+----+------+ 
| 1 | first name |   1 | 1 | F | 
| 3 | sec name |   2 | 2 | G | 
| 6 | fourth name |   2 | 2 | G | 
+----+-------------+-------------+----+------+

左连接查询：

select * from A as a left join division on division.id = a.division_id;

LEFT JOIN结果：

+----+-------------+-------------+------+------+ 
| id | name  | division_id | id | type | 
+----+-------------+-------------+------+------+ 
| 1 | first name |   1 | 1 | F | 
| 3 | sec name |   2 | 2 | G | 
| 6 | fourth name |   2 | 2 | G | 
| 5 | 3rd name |  NULL | NULL | NULL | 
+----+-------------+-------------+------+------+

来源

2016-01-25 bigData

你可以使用'where'条款的加入后，但如果你表现出的分贝结构，一些样本数据，你想要的结果，你会得到更好的答案。 – davejal

如果你想左连接，您可以在createAlias提到它。默认为inner join

Criteria cr = this.sessionFactory.getCurrentSession().createCriteria(A.class, "a") 
     .createAlias("a.division", "division", CriteriaSpecification.LEFT_JOIN);  // Add join type    
List<A> list = cr.list();

CriteriaSpecification.LEFT_JOIN

来源

2016-01-26 06:37:50

Hibernate criteriaQuery - 左连接

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