Here is a custom query that returns the authors who sold at least one book:

public class ExtendedAuthorRepositoryImpl implements ExtendedAuthorRepository {

  @PersistenceContext protected EntityManager entityManager;

  @Override
  public Page<AuthorDAO> findAuthorsWithSoldBooks(
      String queryExpression, String sortExpression, @NonNull Pageable pageable) {
    final CriteriaBuilder builder = entityManager.getCriteriaBuilder();
    final CriteriaQuery<AuthorDAO> query = builder.createQuery(AuthorDAO.class);

    final Root<AuthorDAO> root = query.from(AuthorDAO.class);
    final Join<AuthorDAO, BookDAO> book =
        root.join(AuthorDAO_.BOOKS, JoinType.INNER);

    final List<Predicate> predicates = new ArrayList<Predicate>();
    predicates.add(builder.greaterThan(book.get("soldCount"), 0));

    // fetch the authors as per the page limit
    final List<T> result =
        entityManager
            .createQuery(query)
            .setFirstResult((int) pageable.getOffset())
            .setMaxResults(pageable.getPageSize())
            .getResultList();

    // create count query
    final CriteriaQuery<Long> countQuery = builder.createQuery(Long.class);
    final Root<AuthorDAO> rootCount = countQuery.from(AuthorDAO.class);
    countQuery
        .select(builder.count(rootCount))
        .where(builder.and(predicates.toArray(new Predicate[predicates.size()])));

    // fetch the count of all authors as per given criteria
    final Long authorCount = entityManager.createQuery(countQuery).getSingleResult();

    // return the page
    return new PageImpl<>(result, pageable, authorCount);
  }

Here is the query generated by Hibernate (I run it on SQL Developer and it worked as expected):

select
    c1_0.id,
    c1_0.name,
    c1_0.surname,
    c1_0.birth_date,
    c1_0.biography
from author c1_0
    join book c2_0 on c1_0.id=c2_0.author_id
where c2_0.sold_count > 0
offset ? rows fetch first ? rows only

Here is the result of the query above on SQL Developer:

1 John   Smith    1970-08-08 Biography 1
2 Peter  Williams 1966-01-15 Biography 2
3 Arthur Mitchel  1981-04-22 Biography 3
4 Dave   Bronson  1988-09-01 Biography 4

Finally, in my test, I tried to retrieve 2 pages of size 2:

final int pageSize = 2;
final int totalPages = 2;
final List<Author> content = IntStream.range(0, totalPages)
  .mapToObj(page -> authorApi.getAuthorsWithSoldBooks(null, null, page, pageSize))
  .map(AuthorsPaged::getContent)
  .flatMap(List::stream)
  .toList();

assertThat(content).hasSize(4); // this fails as content has size 3

The problem is that in the first call to findAuthorsWithSoldBooks(), getResultList() returns only the first record

• 1 John Smith

instead of the first 2 records

• 1 John Smith
• 2 Peter Williams

Then, in the second call to findAuthorsWithSoldBooks(), getResultList() returns the first 2 records, again

• 1 John Smith
• 2 Peter Williams

instead of the last 2 records

• 3 Arthur Mitchel
• 4 Dave Bronson

Am I missing something?

UPDATE
Here is the source of authorApi.getAuthorsWithSoldBooks:

public AuthorsPaged getAuthorsWithSoldBooks(
  final String queryExpression,
  final String sortExpression,
  final Integer page,
  final Integer size) {
  final Page<AuthorDTD> AuthorPage = authorRepository.findAuthorsWithSoldBooks(
    queryExpression,
    sortExpression,
    PageRequest.of(page, size));

  return authorConverter.convert(AuthorPage);
}

Logs:

16:49:23.334 TRACE [POLICY_DFLT|1|0|190101|190101] - [org.hibernate.orm.jdbc.bind] - binding parameter [1] as [INTEGER] - [0] 
16:49:23.334 TRACE [POLICY_DFLT|1|0|190101|190101] - [org.hibernate.orm.jdbc.bind] - binding parameter [2] as [INTEGER] - [2] 
16:49:23.459 TRACE [POLICY_DFLT|1|0|190101|190101] - [org.hibernate.orm.jdbc.bind] - binding parameter [1] as [INTEGER] - [2] 
16:49:23.459 TRACE [POLICY_DFLT|1|0|190101|190101] - [org.hibernate.orm.jdbc.bind] - binding parameter [2] as [INTEGER] - [2]