需要帮助才能用JPQL编写无子查询的查询

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
import java.util.List;

public class JPQLExample {
    public static void main(String[] args) {
        // 创建EntityManagerFactory
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("your-persistence-unit-name");
        
        // 创建EntityManager
        EntityManager em = emf.createEntityManager();
        
        // 编写JPQL查询语句
        String jpql = "SELECT e FROM Employee e WHERE e.salary > :salary";
        
        // 创建Query对象
        Query query = em.createQuery(jpql);
        
        // 设置查询参数
        query.setParameter("salary", 5000);
        
        // 执行查询
        List<Employee> employees = query.getResultList();
        
        // 处理查询结果
        for (Employee employee : employees) {
            System.out.println(employee.getName());
        }
        
        // 关闭EntityManager和EntityManagerFactory
        em.close();
        emf.close();
    }
}