내부 조인
SELECT m FROM Member m [INNER] JOIN m.team t
외부 조인
SELECT m FROM Member m LEFT [OUTER] JOIN m.team t
세타 조인
SELECT count(m) from Member m, Team t where m.username = t.name
연관관계 없는 엔티티 외부 조인
SELECT m, t
FROM Member m
LEFT JOIN Team t
ON m.usernmae = t.name