[QueryDSL] 정렬 - orderBy()

 

 

 

 

 

 

정렬

정렬은 orderBy()를 사용하여 수행할 수 있습니다.

 

 

• desc(), asc() : 내림차순, 오름차순
• nullsLast() : null 인 경우 가장 마지막에 위치합니다.
• nullsFirst() : null 인 경우 가장 처음에 위치합니다.

 

 

 

 

 

 

 

setup 코드

@BeforeEach
fun before() {
    val teamA = Team(name = "teamA")
    val teamB = Team(name = "teamB")
    em.persist(teamA)
    em.persist(teamB)
    
    val members = listOf(
        Member(username = "member1", age = 10, team = teamA),
        Member(username = "member2", age = 20, team = teamA),
        Member(username = "member3", age = 30, team = teamB),
        Member(username = "member4", age = 40, team = teamB),
        Member(username = "member5", age = 50, team = teamA),
        Member(username = "member6", age = 60, team = teamA),
        Member(username = "member7", age = 70, team = teamB),
        Member(username = "member8", age = 80, team = teamB),
        Member(username = "member9", age = 90, team = teamA),
        Member(username = "member10", age = 100, team = teamA),
        Member(username = "member11", age = 110, team = teamB),
        Member(username = "member12", age = 120, team = teamB),
    )
    members.forEach { em.persist(it) }
    em.flush()
    em.clear()
}

 

 

 

 

예시

/**
 * 1. 회원 나이 내림차순
 * 2. 회원 이름 오름차순
 * 단 2에서 회원 이름이 없으면(빈 문자열이 아닌 진짜 null) 마지막에 출력
 */
@Test
@DisplayName("정렬")
fun testSort() {
    //given
    em.persist(Member(username = null, age = 100 ))
    em.persist(Member(username = "", age = 100 ))
    em.persist(Member(username = "member6", age = 100 ))
    em.persist(Member(username = "member7", age = 100 ))

    //when
    val fetch = query.selectFrom(member)
        .where(member.age.eq(100))
        .orderBy(
            member.age.desc(),
            member.username.asc().nullsLast()
        )
        .fetch()

    //then
    val memberEmptyUsername = fetch[0]
    val member6 = fetch[1]
    val member7 = fetch[2]
    val memberNull = fetch[3]

    assertThat(memberEmptyUsername.username).isEqualTo("")
    assertThat(memberEmptyUsername.username).isEmpty()
    assertThat(member6.username).isEqualTo("member6")
    assertThat(member7.username).isEqualTo("member7")
    assertThat(memberNull.username).isNull()

}

 

 

 

 

 

 

 

 

 

Reference

실전! Querydsl - 인프런 | 강의