Here below is a subquery to retrieve a list of ids:

protected Long getIdList(
        @NonNull final CriteriaBuilder rootBuilder,
        @NonNull final CriteriaQuery<?> rootQuery,
        @NonNull final Pageable pageable) {
    final HibernateCriteriaBuilder listBuilder = (HibernateCriteriaBuilder) rootBuilder;
    final JpaCriteriaQuery<Long> listQuery = listBuilder.createQuery(Long.class);
    final SqmSubQuery<Tuple> subQuery = (SqmSubQuery<Tuple>) listQuery.subquery(Tuple.class);
    final SqmQuerySpec<Tuple> rootQuerySpec = ((SqmSelectStatement) rootQuery).getQuerySpec();
    final SqmQuerySpec<Tuple> subQuerySpec = rootQuerySpec.copy(SqmCopyContext.simpleContext());
    subQuery.setQueryPart(subQuerySpec);
    final Root<?> subRoot = subQuery.getRoots().iterator().next();
    subQuery.multiselect(subRoot.get("id").alias("id"));

    // listQuery.multiselect(listBuilder.count(listBuilder.literal(1))).from(subQuery);
    // instead of counting the ids, I want to get them...
    listQuery.multiselect(subRoot.get("id")).from(subQuery);

    return entityManager
        .createQuery(listQuery)
        .setFirstResult(PageableUtils.getOffsetAsInteger(pageable))
        .setMaxResults(pageable.getPageSize())
        .getResultList();
}

Unfortunately it doesn’t work and I always get this error message:

org.springframework.orm.jpa.JpaSystemException: Could not locate TableGroup

Any hint would be appreciated. Thanks.