QueryBuilder 提取关系，例如使用 find() 方法

Question

我有 Post 个实体，每个 Post 有 N 条评论。我想提取评论最多的帖子，但是我还想提取 Post 的其他关系，例如作者（用户实体）

使用find()方法我可以做到：

postRepository.find({ relations: ["author", "headingImage"] });

但这不允许我根据需要正确过滤数据 (GROUP BY)。

// UP to here I have the top posts now I have to also load the other informations
const data = await Post.createQueryBuilder("post")
  .addSelect("COUNT(comment.id)", "post_comments_cnt")
  .leftJoin("post.comments", "comments")
  .groupBy("post.id")
  .orderBy("post_comments_cnt", "DESC")
  .take(take)
  .skip(skip)
  .getMany();

如果我还想加载关系怎么办？

const relations = ["author", "headingImage"];

const data = await Post.createQueryBuilder("post")
  ...
  .loadAllRelationIds({ relations })
  .loadRelationCountAndMap("post.commentCount", "course.comments")
  .getMany();

Answer 1

要加载关系，请将 leftJoinAndSelect 添加到查询中。

const data = await Post.createQueryBuilder("post")
  .addSelect("COUNT(comment.id)", "post_comments_cnt")
  .leftJoinAndSelect("post.author", "author")
  .leftJoinAndSelect("post.headingImage", "headingImage")
  .leftJoin("post.comments", "comments")
  .groupBy("post.id")
  .orderBy("post_comments_cnt", "DESC")
  .take(take)
  .skip(skip)
  .getMany();

QueryBuilder 提取关系，例如使用 find() 方法

QueryBuilder extract relations like with find() method

foreign-keys

typescript

typeorm

typeorm-datamapper