JPA 공부 16 - JPQL . 4 JOIN

            Team team =  new Team("team1");
            em.persist(team);

            //샘플 데이터
            Member member = new Member("user",10);
            member.setTeam(team);
            em.persist(member);

            em.flush();
            em.clear();


            // inner join (inner 생략가능)
            String query = "select m from Member m inner join m.team t";
            List<Member> result = em.createQuery(query, Member.class)
                    .getResultList();
            
            // left outer join (outer 생략가능)
            String query2 = "select m from Member m left outer join m.team t";
            List<Member> result2 = em.createQuery(query2, Member.class)
                    .getResultList();
            
            // on 절로 join의 조건 추가             
            String query3 = "select m from Member m inner join m.team t on  t.name = 'team1'";
            List<Member> result3 = em.createQuery(query3, Member.class)
                    .getResultList();
            
            //연관관계가 없는 엔티티 외부 조인 
            String query4 = "select m from Member m left join Team t on m.username = t.name ";
            List<Member> result4 = em.createQuery(query4, Member.class)
                    .getResultList();