Hibernate criteriaQuery - 左連接

如何使用條件查詢來應用左連接，我只能在Internet上查找內連接條件。Hibernate criteriaQuery - 左連接

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

除法是一個存在於A類中的實體，這是返回我的內部連接結果。我想申請左連接上劃分實體：

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

表的數據：

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

表分割後的數據：

id type 
    1 F 
    2 G

內連接：

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

內加入的結果：

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

左連接查詢：

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

LEFT JOIN結果：

+----+-------------+-------------+------+------+ 
| 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 | 
+----+-------------+-------------+------+------+

來源

2016-01-25 bigData

你可以使用'where'條款的加入後，但如果你表現出的分貝結構，一些樣本數據，你想要的結果，你會得到更好的答案。 – davejal

如果你想左連接，您可以在createAlias提到它。默認爲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

來源

2016-01-26 06:37:50

Hibernate criteriaQuery - 左連接

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