hibernate - Grails-非法尝试取消引用Hql中的收集错误

我有一个培训 Realm 类(class)

    class Training {

     String type
     Date createdOn
     Date modifiedOn

    static belongsTo = [course: Course]
    static hasMany = [attachments: Attachment]
  }

我有类(class) Realm 类(class)

     class Course {

          String name

          static hasMany = [trainings: Training, tracks: Track]
          static belongsTo = Track
   }

和跟踪域类

    class Track {
        String name
    }

我想选择基于轨迹的训练。

现在说我得到了轨道ID，我想根据轨道ID检索训练

我试图查询这样的事情

 def query = "FROM Training AS t WHERE  t.course.tracks.id IN (1,2)"
  trainingList = Training.findAll(query)

它给

 illegal attempt to dereference collection

错误..因为我不能做t.course.tracks.id
如果我有曲目ID(例如1、2)，请帮助我编写正确的hql查询以获得培训

最佳答案

你能做的就是这个

def query = "FROM Training AS t join t.course as c join c.tracks as tr WHERE  tr.id IN (1,2)"
trainingList = Training.findAll(query)

问题是，当您尝试从一个变为多个时。