Node.js 使用Sequelize在多对多关联中遇到的令人惊讶的问题

我创建了三个表post、tags和post_标记。每个帖子通过PostTags属于多个标签，每个标签通过PostTag属于多个帖子。令人惊讶的问题是，当我将posts.id排序为

DESC

时，标记将为空，并且连接查询结果不会返回任何标记。但是当我将

id

排序为

ASC

时，标记将显示在结果JSON中。有些帖子没有标签。我不知道为什么会有这个问题。如果知道数据库的类型有助于解决问题，我将使用Postgresql

模型结构为：

// Posts Model
const posts = (sequelize, DataTypes) => {
  const posts = sequelize.define(
    "posts",
    {
      userId: DataTypes.INTEGER,
      title: DataTypes.STRING,
    },
    {
      tableName: "posts",
      timestamps: true,
      paranoid: true
    }
  );

  // Relations
  posts.associate = (models) => {
    posts.belongsToMany(models.tags, {
      through: 'postTags',
      as: 'tags',
      foreignKey: 'postId',
      otherKey: 'tagId'
    });
  }

  return posts;
};

// Tags Model
const tags = sequelize.define(
    "tags",
    {
      title: DataTypes.STRING
    },
    {
      tableName: "tags",
      timestamps: true,
      paranoid: true
    }
  );

  // Relations
  tags.associate = (models) => {
    tags.belongsToMany(models.posts, {
      through: 'postTags',
      as: 'posts',
      foreignKey: 'tagId',
      otherKey: 'postId'
    });
  }

  return tags;
};

// PostTags Model
const post_tags = (sequelize, DataTypes) => {
  const post_tags = sequelize.define(
    "postTags",
    {
      postId: DataTypes.INTEGER,
      tagId: DataTypes.INTEGER
    },
    {
      tableName: "post_tags",
      timestamps: true,
      paranoid: true
    }
  );

  return post_tags;
};

const posts = models.posts.findAll({
   attributes: [
     'id',
     'title'
   ],
   include: [
      {
         model: models.tags,
         as: 'tags',
         required: false,
         attributes: [
            'id',
            'title'
         ],
         through: {
            model: models.postTags,
            as: 'postTags',
            attributes: [
               'postId',
               'tagId'
            ]
         }
       }
   ],
   order: [['id', 'desc']]
 });

我通过以下选项选择了行：

// Posts Model
const posts = (sequelize, DataTypes) => {
  const posts = sequelize.define(
    "posts",
    {
      userId: DataTypes.INTEGER,
      title: DataTypes.STRING,
    },
    {
      tableName: "posts",
      timestamps: true,
      paranoid: true
    }
  );

  // Relations
  posts.associate = (models) => {
    posts.belongsToMany(models.tags, {
      through: 'postTags',
      as: 'tags',
      foreignKey: 'postId',
      otherKey: 'tagId'
    });
  }

  return posts;
};

// Tags Model
const tags = sequelize.define(
    "tags",
    {
      title: DataTypes.STRING
    },
    {
      tableName: "tags",
      timestamps: true,
      paranoid: true
    }
  );

  // Relations
  tags.associate = (models) => {
    tags.belongsToMany(models.posts, {
      through: 'postTags',
      as: 'posts',
      foreignKey: 'tagId',
      otherKey: 'postId'
    });
  }

  return tags;
};

// PostTags Model
const post_tags = (sequelize, DataTypes) => {
  const post_tags = sequelize.define(
    "postTags",
    {
      postId: DataTypes.INTEGER,
      tagId: DataTypes.INTEGER
    },
    {
      tableName: "post_tags",
      timestamps: true,
      paranoid: true
    }
  );

  return post_tags;
};

const posts = models.posts.findAll({
   attributes: [
     'id',
     'title'
   ],
   include: [
      {
         model: models.tags,
         as: 'tags',
         required: false,
         attributes: [
            'id',
            'title'
         ],
         through: {
            model: models.postTags,
            as: 'postTags',
            attributes: [
               'postId',
               'tagId'
            ]
         }
       }
   ],
   order: [['id', 'desc']]
 });

---

您是否将sequelize查询记录到console？我从未对此有过任何异议，但您可能会在查询中得到您不期望的结果。。。如果您记录它们，请将它们粘贴到您的问题中…

是的，控制台中没有任何错误！我截断表，再次插入post和标记！现在问题解决了！我不知道为什么！：-|我不是故意犯错的。。。sequelize将输出它在开发中调用的所有查询。。。当我发现并启用它时，在排除爬行的奇怪东西时非常有用。查询日志现在在控制台中打印。但是我测试了许多在表中插入数据的类型，最后一个问题不存在！因此，现在我无法显示查询输出。如果问题再次出现，我会告诉你。好东西，很高兴你能成功。。。干杯