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JPQL IS NULL expression

[Updated: May 16, 2018, Created: May 16, 2018]

Following example shows how to use IS NULL to find properties values which have not been set.

Example

Entity

@Entity
public class Employee {
  @Id
  @GeneratedValue
  private long id;
  private String name;
  private String dept;
  private long salary;
    .............
}

Using IS NULL

public class ExampleMain {
  private static EntityManagerFactory entityManagerFactory =
          Persistence.createEntityManagerFactory("example-unit");

  public static void main(String[] args) {
      try {
          persistEmployees();
          findEmployeeByDeptNull();
          findEmployeeByDeptNotNull();

      } finally {
          entityManagerFactory.close();
      }
  }

  public static void persistEmployees() {
      Employee employee1 = Employee.create("Diana", "IT", 3000);
      Employee employee2 = Employee.create("Rose", "Sales", 2000);
      Employee employee3 = Employee.create("Denise", "Admin", 4000);
      Employee employee4 = Employee.create("Mike", null, 3500);
      EntityManager em = entityManagerFactory.createEntityManager();
      em.getTransaction().begin();
      em.persist(employee1);
      em.persist(employee2);
      em.persist(employee3);
      em.persist(employee4);
      em.getTransaction().commit();
      em.close();
  }

  private static void findEmployeeByDeptNull() {
      System.out.println("-- Employees with dept is NULL --");
      EntityManager em = entityManagerFactory.createEntityManager();
      Query query = em.createQuery(
              "SELECT e FROM Employee e WHERE e.dept IS NULL");
      List<Employee> resultList = query.getResultList();
      resultList.forEach(System.out::println);
      em.close();
  }

  private static void findEmployeeByDeptNotNull() {
      System.out.println("-- Employees with dept is NOT NULL --");
      EntityManager em = entityManagerFactory.createEntityManager();
      Query query = em.createQuery(
              "SELECT e FROM Employee e WHERE e.dept IS NOT NULL");
      List<Employee> resultList = query.getResultList();
      resultList.forEach(System.out::println);
      em.close();
  }
}
-- Employees with dept is NULL --
Employee{id=4, name='Mike', dept='null', salary=3500}
-- Employees with dept is NOT NULL --
Employee{id=1, name='Diana', dept='IT', salary=3000}
Employee{id=2, name='Rose', dept='Sales', salary=2000}
Employee{id=3, name='Denise', dept='Admin', salary=4000}

Example Project

Dependencies and Technologies Used:

  • h2 1.4.197: H2 Database Engine.
  • hibernate-core 5.2.13.Final: The core O/RM functionality as provided by Hibernate.
    Implements javax.persistence:javax.persistence-api version 2.1
  • JDK 1.8
  • Maven 3.3.9

JPQL IS NULL expression Select All Download
  • jpql-is-null-example
    • src
      • main
        • java
          • com
            • logicbig
              • example
                • ExampleMain.java
          • resources
            • META-INF

    See Also