如何使用 Spring Data JPA 根据来自另一个实体的列检索实体的数据？

Question

我有一个目标表、一个比赛表和一个比赛表。 每个目标都有一个 matchId，每个比赛都有一个 CompetitionId，所以如果我想从比赛中检索所有目标，我会这样做：

select * from mydb.goal g
JOIN mydb.matches m
ON g.goal_match = m.matchid
JOIN mydb.competitions c
ON m.competition = c.competitionid
WHERE c.competitionid = 219; 

我有一个 Spring data JPA 项目，我有 3 个实体这是目标：

@Entity
public class Goal {

@Id
private long idgoal;
@ManyToOne(optional = false, fetch = FetchType.LAZY)
@JoinColumn(name = "goalMatch")
private Match goalMatch;

public long getIdgoal() {
    return idgoal;
}

public void setIdgoal(long idgoal) {
    this.idgoal = idgoal;
}

public Match getGoalMatch() {
    return goalMatch;
}

public void setGoalMatch(Match goalMatch) {
    this.goalMatch = goalMatch;
}

}

这是比赛

@Entity(name = "matches")
public class Match {

@Id
@GeneratedValue
private long idmatch;
@ManyToOne(optional = false, fetch = FetchType.LAZY)
@JoinColumn(name = "competition")
private Competition competition;

public long getIdmatch() {
    return idmatch;
}

public void setIdmatch(long idmatch) {
    this.idmatch = idmatch;
}

public Competition getCompetition() {
    return competition;
}

public void setCompetition(Competition competition) {
    this.competition = competition;
}

}

和竞争：

@Entity(name = "competitions")
public class Competition {

@Id
private Long idcompetitions;

public Long getIdcompetitions() {
    return idcompetitions;
}
public void setIdcompetitions(Long idcompetitions) {
    this.idcompetitions = idcompetitions;
}
}

然后我有我的目标存储库，我试图找到一种方法来从比赛中检索所有目标，但我找不到方法来做到这一点，除非使用很长的 @Query。

Spring Data JPA 是否有直接的方式来做到这一点？ 还是我应该只使用自定义 @Query？

Answer 1

JB Nizet 非常接近：

正确的查询是：

@Query("select g from Goal g where g.goalMatch.competition.idcompetitions = :competitionId")