Question 32

Explanation

Asc and desc

Here's a code example demonstrating the usage of the ordering operators "Asc" and "Desc" in a custom finder method declaration in a Spring Data JPA Repository Interface:

public interface UserRepository extends JpaRepository<User, Long> {
    List<User> findAllByOrderByLastNameAsc();
    List<User> findAllByOrderByAgeDesc();
}

In the above example, the UserRepository interface extends JpaRepository and defines two custom finder methods. The method findAllByOrderByLastNameAsc() returns a list of users sorted in ascending order by their last name. The method findAllByOrderByAgeDesc() returns a list of users sorted in descending order by their age.

Note that the ordering operators "Asc" and "Desc" are appended to the property names (e.g., "LastName" and "Age") to indicate the desired sorting order.

Please ensure that you have the necessary entities (e.g., User class) and the appropriate configuration in place for Spring Data JPA to work correctly.

Springdoc:

The query builder mechanism built into the Spring Data repository infrastructure is useful for building constraining queries over entities of the repository.

The following example shows how to create a number of queries:

Example 13. Query creation from method names

interface PersonRepository extends Repository<Person, Long> {
 
  List<Person> findByEmailAddressAndLastname(EmailAddress emailAddress, String lastname);
 
  // Enables the distinct flag for the query
  List<Person> findDistinctPeopleByLastnameOrFirstname(String lastname, String firstname);
  List<Person> findPeopleDistinctByLastnameOrFirstname(String lastname, String firstname);
 
  // Enabling ignoring case for an individual property
  List<Person> findByLastnameIgnoreCase(String lastname);
  // Enabling ignoring case for all suitable properties
  List<Person> findByLastnameAndFirstnameAllIgnoreCase(String lastname, String firstname);
 
  // Enabling static ORDER BY for a query
  List<Person> findByLastnameOrderByFirstnameAsc(String lastname);
  List<Person> findByLastnameOrderByFirstnameDesc(String lastname);
}

https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories.query-methods.query-creation

See also: Order the results of a derived query

You can, of course, also order your query results. In JPQL, this would require an ORDER BY clause in your query. With Spring Data JPA, you just need to add the words OrderBy to your query followed by the name of the entity attribute and the abbreviations ASC or DESC for your preferred order.

The following example uses this feature to retrieve all Book entities whose title contains a provided String in the ascending order of their title.

public interface BookRepository extends JpaRepository<Book, Long> {
 
    List<Book> findByTitleContainsOrderByTitleAsc(String title);
 
}

When you call this method on the BookRepository, Spring Data JPA and Hibernate generate an SQL statement with the expected ORDER BY clause.

select
        book0_.id as id1_1_,
        book0_.title as title2_1_,
        book0_.version as version3_1_ 
    from
        book book0_ 
    where
        book0_.title like ? 
    order by
        book0_.title asc

https://thorben-janssen.com/ultimate-guide-derived-queries-with-spring-data-jpa