Convert specific query into JPQL or Criteria Builder query - spring-data-jpa

Question

Here is the code for 2 entities (it generates three tables in the database). A Book entity:
#Entity
public class Book {
#Id
private long id;
private String name;
#ManyToMany
private List<Author> authors;
}
An Author entity:
#Entity
public class Author {
#Id
private long id;
#Column(unique=true)
private String name;
}
I'm trying to find books by the list of authors. Here is a sql query:
select book.id, ARRAY_AGG(author.name)
from book
join book_authors ba on book.id=ba.book_id
join author on ba.authors_id=author.id
group by book.id
having ARRAY_AGG(distinct author.name order by author.name)=ARRAY['a1', 'a2']::varchar[]
['a1', 'a2'] is a list of book authors, it must be passed as a parameter. The idea is to aggregate authors and then compare them with the list of passed parameters.
How to rewrite this SQL-query into either a JPQL or CriteriaBuilder query?

Answer 1

#Query("select distinct b from Book b join b.authors a where a.name in(:names)")
List<Book> findByAuthorsNames(#Param("names") List<String> names)
If you want to fetch b.authors use join fetch instead of join

Answer 2

If the exact match is necessary you can use Specification like this
public class BookSpecifications {
public static Specification<Book> byAuthorsNames(List<String> names) {
return (root, query, builder) -> {
Join<Book, Author> author = root.join("authors", JoinType.LEFT);
Predicate predicate = builder.conjunction;
for(String name : names) {
Predicate namePredicate = builder.and(author.get("name"), name);
predicate = builder.and(predicate, namePredicate);
}
return predicate;
}
}
}
BookRepository have to extend JpaSpecificationExecutor.
Usage:
BookRepository repository;
public List<Book> findByAuthorsNames(List<String> names) {
return repository.findAll(BookSpecifications.byAuthorsNames(names));
}