JpaSpecificationExecutor JOIN + ORDER BY in Specification

Question

I have a query using a JOIN and ORDER BY and want to use it within my repository using the Criteria Api.

Here I found, how to wrap such a query into a CriteriaQuery

Answer 1

Try something like this (I assumed pet has many owners):

public static Specification<Pet> ownerNameEqual(String ownerName) {
        return new Specification<Pet>() {
            @Override
            public Predicate toPredicate(Root<Pet> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                Join<Pet, Owner> owners = root.join("owners");
                criteriaQuery.orderBy(criteriaBuilder.desc(root.get("id")));
                return criteriaBuilder.equal(owners.get("name"), ownerName);
            }
        };
    }

This is just an example to search all pets whose at least one owner has name equal to ownerName

But you could add a method List<Pet> findByOwnersNameOrderByIdDesc(String ownerName); in your repository instead (as an equivalent to Specification).