TypeORM - 3 个相关表之间的 LEFT JOIN/INNER JOIN 问题答案

【问题标题】：TypeORM - Problem with LEFT JOIN/ INNER JOIN between 3 related tablesTypeORM - 3 个相关表之间的 LEFT JOIN/INNER JOIN 问题
【发布时间】：2019-08-12 23:02:00
【问题描述】：

所以我有一些我无法处理的问题，也许你可以帮助我。所以：我有三个实体——用户、团队、用户团队，其中包含（userId、teamId、teamRole）。 UserTeam 是包含复合主键的实体。就像下面的代码：

@Index(["teamId", "userId"], { unique: true })
export class UserTeam {

    @PrimaryColumn("int")
    userId = undefined;

    @PrimaryColumn("int")
    teamId = undefined;

    @ManyToOne(type => Team)
    team = undefined;

    @ManyToOne(type => User)
    user = undefined;

    @Column({
        type: 'enum',
        enum: ['CAPITAN', 'PLAYER'],

    })
    teamRole = "";
}

export class Team {

    @PrimaryGeneratedColumn()
    id = undefined; 
@OneToMany(type => UserTeam, userTeam => userTeam.user)
    userTeams = undefined;

export class User {

    @PrimaryGeneratedColumn()
    id = undefined;

    @OneToMany(type => UserTeam, userTeam => userTeam.team)
    teams = undefined;
}

所以 -> 我想创建一个查询，它将返回特定团队的所有玩家（用户）。所以我创建了一个查询，例如 eq ({team_id: 1, player: {userId:1, userId:21,userId:34} （而不是 ids，我希望对象只是示例。

getRepository(Team).createQueryBuilder("team")
            .leftJoin("team.users", "userTeam")
            .leftJoin("userTeam.user", "user")
            .getMany()

返回给我QUERY：

SELECT "team"."id" AS "team_id", "team"."name" AS "team_name", "team"."shortcut" AS "team_shortcut", "team"."nationality" AS "team_nationality", "team"."description" AS "team_description", "team"."imagePath" AS "team_imagePath", "team"."division" AS "team_division" FROM "team" "team" LEFT JOIN "user_team" "userTeam" ON "userTeam"."userId"="team"."id"  LEFT JOIN "user" "user" ON "user"."id"="userTeam"."userId"

问题就在那里，因为我有

 LEFT JOIN "user_team" "userTeam" ON "userTeam"."userId"="team"."id"```

代替

userTeam.teamId=team.id

您对如何解决我的问题有任何想法吗？我会很高兴收到任何建议和提示。

【问题讨论】：

标签： javascript postgresql typescript orm typeorm

【解决方案1】：

问题已解决。我有反向关系。我应该有

@OneToMany(type => UserTeam, userTeam => userTeam.user)
    teams = undefined;

@OneToMany(type => UserTeam, userTeam => userTeam.team)
    users = undefined;

【讨论】：