是否可以使用HQL查詢連接表？

Question

我的數據庫：

WorkflowProcess 
id | name 

WorkflowProcessToWorkflowProcess 
ancestor | descendent 

我需要查詢根WorkflowProcess。有了這個表結構，我在找查詢類似SELECT * FROM WorkflowProcess WHERE id NOT IN (SELECT DISTINCT descendent FROM WorkflowProcessToWorkflowProcess)

我WorkflowProcess實體：

private Collection<WorkflowProcessEntity> workflowProcesses; 

@JoinTable(name = "Workflow_Process_to_Workflow_Process", joinColumns = { 
     @JoinColumn(name = "ancestor", referencedColumnName = "id")}, inverseJoinColumns = { 
     @JoinColumn(name = "descendent", referencedColumnName = "id")}) 
@ManyToMany() 
public Collection<WorkflowProcessEntity> getWorkflowProcesses() { 
    return workflowProcesses; 
} 

public void setWorkflowProcesses(Collection<WorkflowProcessEntity> workflowProcesses) { 
    this.workflowProcesses = workflowProcesses; 
} 

是否有可能與HQL做到這一點？

Answer 1

嘗試這樣：

select child 
from WorkflowProcess parent right join parent.workflowProcesses child 
where parent is null