java Entitymanager 在 2 个不同表中使用内部连接查询
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Entitymanager query in 2 different tables with inner join
提问by galao
my current code:
我目前的代码：
TypedQuery<Account> tp = em.createQuery("SELECT a FROM Account a INNER JOIN User u ON u.account_id = a.id WHERE a.email = :email AND a.pwd = :pwd AND a.role = 'admin'", Account.class);
tp.setParameter("email", this.username);
tp.setParameter("pwd", this.password);
Account result = tp.getSingleResult();
but ill get an java.lang.IllegalArgumentException.
但我会得到一个 java.lang.IllegalArgumentException。
what i need is to display a column in the user table.
我需要的是在用户表中显示一列。
something like String name = Account.getName();but the Account entity doesnt have a getName() only the User entity has.
类似于String name = Account.getName();但 Account 实体没有 getName() 只有 User 实体有。
*update
*更新
this is the error
这是错误
java.lang.IllegalArgumentException: An exception occurred while creating a query in EntityManager: Exception Description: Syntax error parsing the query [SELECT a FROM Account a INNER JOIN User u ON u.account_id = a.id WHERE a.email = :email AND a.pwd = :pwd AND a.role = 'admin']. Internal Exception: org.eclipse.persistence.internal.libraries.antlr.runtime.EarlyExitException
java.lang.IllegalArgumentException：在 EntityManager 中创建查询时发生异常：异常描述：语法错误解析查询 [SELECT a FROM Account a INNER JOIN User u ON u.account_id = a.id WHERE a.email = :email AND a.pwd = :pwd AND a.role = 'admin']。内部异常：org.eclipse.persistence.internal.libraries.antlr.runtime.EarlyExitException
回答by Elo
Thisarticle explains you have to JOIN like that : you specifiy the table names separated by a coma, and you move the ONcondition in the WHERE.
这篇文章解释了你必须像这样加入：你指定用逗号分隔的表名，然后ON在WHERE.
TypedQuery<Account> tp = em.createQuery("SELECT a FROM Account a, User u WHERE u.account_id = a.id AND a.email = :email AND a.pwd = :pwd AND a.role = 'admin'", Account.class);
tp.setParameter("email", this.username);
tp.setParameter("pwd", this.password);
Account result = tp.getSingleResult();
回答by SudoRahul
Try this.
试试这个。
result.getUser().getName();
result.getUser().getName();
This, though, is under the assumption, that your Account class has a relationship with the User class.
但是，这是在假设您的 Account 类与 User 类有关系的情况下。
The assumption of this being Hibernate/JPArelationship comes from your previous questionand the use HQLin your code above.
这是Hibernate/JPA关系的假设来自您之前的问题以及上面代码中的 use HQL。
