JPA-10 SubQuery

JPQL도 SQL처럼 서브 쿼리를 지원한다.
사용 가능 : where, having절
사용 불가능 : select, from절

@Test
	public void 서브쿼리를_이용한_메뉴_조회_테스트() {
		
		//given
		String categoryNameParameter = "한식";
		
		//when
		String jpql ="SELECT m FROM section07_menu m WHERE m.categoryCode"
					+ "=(SELECT c.categoryCode FROM section07_category c WHERE c.categoryName = :categoryName)";
		
		List<Menu> menuList = entityManager.createQuery(jpql, Menu.class)
				.setParameter("categoryName", categoryNameParameter)
				.getResultList();
		
		//then
		assertNotNull(menuList);
		menuList.forEach(System.out::println);
	}