在ManyToMany关系中没有项目的实体的JPQL

Question

简单的JPA/JPQL问题.我有一个具有ManyToMany关系的实体:

@Entity
public class Employee {      
  @ManyToMany
  @JoinTablename="employee_project"
      joinColumns={@JoinColumn(name="employee_id"}
      inverseJoinColumns={@JoinColumn(name="project_id"})
  private List<Project> projects;

什么是JPQL查询以返回没有任何项目的所有Employees？

Answer 1

from Employee e where not exists elements(e.projects)

要么

from Employee e where size(e.projects) = 0