The @Query annotation can also be used to declare native queries. For that we need to set the @Query#nativeQuery flag to true.

Example

Entity

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

The repository

package com.logicbig.example;

import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;
import java.util.List;

public interface EmployeeRepository extends CrudRepository<Employee, Long> {

    @Query(value = "SELECT max(avg_sal), min(avg_sal) FROM (SELECT dept , avg(salary) as avg_sal "
            + "from Employee  GROUP BY dept HAVING dept in ?1) ", nativeQuery = true)
    public Object[][] findMaxMinAvgSalariesOfDept(List<String> deptNames);
}

Example Client

@Component
public class ExampleClient {

    @Autowired
    private EmployeeRepository repo;

    public void run() {
        List<Employee> employees = createEmployees();
        repo.saveAll(employees);

        System.out.println(" -- finding all employees --");
        Iterable<Employee> all = repo.findAll();
        all.forEach(System.out::println);

        System.out.println(" -- finding max/min of average salaries in Admin and IT depts  --");
        Object[][] maxAvgSalaries = repo.findMaxMinAvgSalariesOfDept(Arrays.asList("Admin", "IT"));
        for (Object[] maxAvgSalary : maxAvgSalaries) {
            System.out.println("max avg salary: " + maxAvgSalary[0]);
            System.out.println("min avg salary: " + maxAvgSalary[0]);
        }
    }

    private List<Employee> createEmployees() {
        return Arrays.asList(
                Employee.create("Diana", "Admin", 2000),
                Employee.create("Mike", "Sale", 1000),
                Employee.create("Rose", "IT", 4000),
                Employee.create("Sara", "Admin", 3500),
                Employee.create("Randy", "Sale", 3000),
                Employee.create("Charlie", "IT", 2500)
        );
    }
}

Main class

public class ExampleMain {

    public static void main(String[] args) {
        AnnotationConfigApplicationContext context =
                new AnnotationConfigApplicationContext(AppConfig.class);
        ExampleClient exampleClient = context.getBean(ExampleClient.class);
        exampleClient.run();
        EntityManagerFactory emf = context.getBean(EntityManagerFactory.class);
        emf.close();
    }
}

 -- finding all employees --
Employee{id=1, name='Diana', dept='Admin', salary=2000}
Employee{id=2, name='Mike', dept='Sale', salary=1000}
Employee{id=3, name='Rose', dept='IT', salary=4000}
Employee{id=4, name='Sara', dept='Admin', salary=3500}
Employee{id=5, name='Randy', dept='Sale', salary=3000}
Employee{id=6, name='Charlie', dept='IT', salary=2500}
 -- finding max/min of average salaries in Admin and IT depts  --
max avg salary: 3250
min avg salary: 3250

Example Project

Dependencies and Technologies Used:

• spring-data-jpa 2.0.7.RELEASE: Spring Data module for JPA repositories.
  Uses org.springframework:spring-context version 5.0.6.RELEASE
• hibernate-core 5.3.1.Final: Hibernate's core ORM functionality.
  Implements javax.persistence:javax.persistence-api version 2.2
• h2 1.4.197: H2 Database Engine.
• JDK 1.8
• Maven 3.3.9