5장 정렬

1)

    /**
     * 회원 정렬 순서
     * 1. 회원 나이 내림차순(desc)
     * 2. 회원 이름 올림차순(asc)
     * 단 2에서 회원 이름이 없으면 마지막에 출력(nulls last)
    */
    @Test
    public void sort(){

        em.persist(new Member(null, 100));
        em.persist(new Member("member5", 100));
        em.persist(new Member("member6", 100));

        List<Member> result = queryFactory
                .selectFrom(member)
                .where(member.age.eq(100))
                .orderBy(member.age.desc(), member.username.asc().nullsLast())
                .fetch();

        Member member5 = result.get(0);
        Member member6 = result.get(1);
        Member memberNull = result.get(2);

        assertThat(member5.getUsername()).isEqualTo("member5");
        assertThat(member6.getUsername()).isEqualTo("member6");
        assertThat(memberNull.getUsername()).isNull();
    }