orderBy oneToMany 关系使用 typeorm

Question

我有 PublicationsEntity 与 LikesEntity 的 OneToMany 关系，我正在尝试按喜欢对我的出版物进行排序，并返回所有喜欢与喜欢关联的用户的喜欢，以及所有 cmet 以在前端显示它们

@Entity('publications')
export class PublicationsEntity {
        @PrimaryGeneratedColumn()
        id: number;
    
        @Column({ type: 'longtext' })
        publication: string;

        @ManyToOne(type => UsersEntity, users => users.publications, { 
        onDelete: "CASCADE" })
        user: UsersEntity;

        @OneToMany(type => CommentsEntity, comments => 
        comments.publication, { onDelete: "CASCADE" })
        comments: CommentsEntity[];
    
        @OneToMany(type => LikesEntity, likes => likes.publication, { onDelete: "CASCADE" })
        likes: LikesEntity[];
    }

有一个我喜欢的实体包含用户，我试图在排序后的出版物中返回每个喜欢的用户：

@Entity('likes')
export class LikesEntity {
    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    like: number;

    @ManyToOne(type => UsersEntity, user => user.likes, { eager: true })
    user: UsersEntity;

    @ManyToOne(type => PublicationsEntity, publication => publication.likes)
    publication: PublicationsEntity;
}

我的用户实体：

@Entity('users')
export class UsersEntity {
    @PrimaryGeneratedColumn()
    id: number;

    @Column({ nullable: true })
    userName: string;

    @OneToMany(type => PublicationsEntity, publications => 
    publications.user, { onDelete: "CASCADE" })
    publications: PublicationsEntity[];

    @Column()
    email: string;

    @Column({ select: false })
    password: string;

    @OneToMany(type => CommentsEntity, comment => comment.user, { onDelete: "CASCADE" })
    comments: CommentsEntity[];

    @OneToMany(type => LikesEntity, like => like.user, { onDelete: "CASCADE" })
    likes: LikesEntity[];

    @OneToMany(type => PublicationsEntity, publications => publications.user, { onDelete: "CASCADE" })
    publications: PublicationsEntity[];

    @CreateDateColumn({ type: "timestamp", default: () => "CURRENT_TIMESTAMP(6)" })
    createdAt: Date;

    @UpdateDateColumn({ type: "timestamp", default: () => "CURRENT_TIMESTAMP(6)", onUpdate: "CURRENT_TIMESTAMP(6)" })
    updatedAt: Date;
}

还有我的 PublicationsService

async getPublications() {
    return await getConnection()
    .createQueryBuilder(PublicationsEntity, 'publications')
    .leftJoinAndSelect('publications.likes', 'likes')
    .leftJoinAndSelect('publications.user', 'user')
    .leftJoinAndSelect('publications.comments', 'comments')
    .leftJoinAndSelect('comments.children', 'children')
    //.orderBy()
    .getMany()
}

我点赞表上的一些数据：https://i.stack.imgur.com/wJ0l5.png

Answer 1

首先，我认为你应该在你的实体上修复一些东西 在您的 PublicationsEntity 中

 @OneToMany(type => LikesEntity, likes => likes.publication, { onDelete: "CASCADE" })
    likes: LikesEntity[]; // this one should be an array

对于 LikesEntity

@ManyToOne(type => PublicationsEntity, publication => publication.likes)
publication: PublicationsEntity;

对于您的问题，我假设您想要返回按赞数排序的出版物，为此您应该在查询中添加：

async getPublications() {
return await getConnection()
.createQueryBuilder(PublicationsEntity, 'publications')
.leftJoin('publications.likes', 'likes')
.addSelect("COUNT(likes.publication) AS total_likes" )
.orderBy('total_likes', 'ASC') // or DESC
.groupBy("likes.publication")
.getRawMany()
  }

更新

据我从您下面的 cmets 中了解到，我认为您需要使用 map 和 sort 功能来获得所需的结果：

async getPublications() {
return await getConnection()
.createQueryBuilder(PublicationsEntity, 'publications')
.leftJoinAndSelect('publications.likes', 'likes')
.leftJoinAndSelect('publications.user', 'user')
.leftJoinAndSelect('publications.comments', 'comments')
.leftJoinAndSelect('comments.children', 'children')
//.orderBy()
.getMany().then(data => data.map(a => ({ ...a, total_likes:a.likes.length })).sort(function (a, b) {
  return b.total_likes - a.total_likes; // this's going to sort by DESC if you want to make the opposite just do a.total_likes - b.total_likes
})
)

}