how to find an employee that has salaries with jpa hibernate-CodePudding

I have a method that returns an Employee by Id with a simple entitymanager.find(id) but now I need to find an employee by id that has a salary assigned to it, (the classes Employee and Salary are mapped through OneToMany), should I use an entityManager.find() or entityManager.createQuery()?

@Override
public Optional<Employee> findById(Long emptNo) {
    try {
        return Optional.ofNullable(this.entityManager.find(Employee.class, emptNo));
    } catch (EmptyResultDataAccessException e) {
        return Optional.empty();
    }
}

This is where i need help:

@Override
public Optional<Employee> findByIdWithSalary(Long empNo) {
    this.entityManager.createQuery("select (e.empNo,s.salary,s.fromDate,s.toDate) as from employees e, salaries s where e.empNo=s.empNo");
    try {
        return Optional.ofNullable(this.entityManager.find(Employee.class, empNo));
    } catch (EmptyResultDataAccessException e) {
        return Optional.empty();
    }
}

CodePudding user response：

you need to change the query like below.

@Override
public Optional<Employee> findByIdWithSalary(Long empNo) {
    this.entityManager.createQuery("select * from employees e left join e.empNo=s.empNo where s.salary >0");
    try {
        return Optional.ofNullable(this.entityManager.find(Employee.class, empNo));
    } catch (EmptyResultDataAccessException e) {
        return Optional.empty();
    }
}

if it does not working send your entity classes. we can do the same with that also.