Playframework 具有EXISTS和关系的SQL查询的JPQL等价物

我正在使用Play Framwork 1.2.4

我创建了3个具有关系的模型类：

标题行-1>线型

@Entity
public class Header extends Model {
   @OneToMany(mappedBy="header" , cascade=CascadeType.ALL)
   public List<Line> lines;
   ...
}

@Entity
public class Line extends Model{
   @ManyToOne
   public Header header ;

  @ManyToOne
   publicLineType lineType;
   ...
}

@Entity
public class LineType extends Model {

   public Integer code ;
   ...
}

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我回答我自己的问题：

Query query = JPA.em().createQuery("select header from Header as header where exists(select line from Line line JOIN ligne.lineType as type where ligne.header=header and type.code='X')");
List<Header> headers = query.getResultList();

内部联接：

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存在：

我没有尝试，因为在我使用JpqlSelect编写查询之前，它似乎非常有限：

Query query = JPA.em().createQuery("select header from Header as header where exists(select line from Line line JOIN ligne.lineType as type where ligne.header=header and type.code='X')");
List<Header> headers = query.getResultList();