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postgresql - Sequelize：返回单个 COUNT 条目而不是嵌套包含中的每一行

问题描述

我正在尝试从 Sequelize 中的嵌套包含中获取总行数（计数）。我在这里关注了无数问题，但似乎无法正确解决。

楷模：

关系：

 // Brand
 Brand.hasOne(models.BrandProfile, {
   foreignKey: 'brand_id',
   as: 'brand_profile'
 })

 // BrandProfile
 BrandProfile.belongsTo(models.Brand, {
   foreignKey: 'brand_id',
 })
 BrandProfile.hasMany(models.BrandPageView, {
   foreignKey: 'brand_id',
   as: 'brand_page_views'
 })

 // BrandPageView
 BrandProfile.belongsTo(models.BrandProfile, {
   foreignKey: 'brand_id',
 })

现在，当我尝试像这样正常运行我的查询时：

const { count, rows } = await Brand.findAndCountAll({
  include: [
    {
      model: BrandProfile,
      as: 'brand_profile',
      include: [
        {
          model: BrandPageView,
          as: 'brand_page_views',
        },
      ],
    },
  ],
})

它返回以下内容：

{
  id: 1,
  created_at: '2020-12-26T20:42:19.930Z',
  updated_at: '2020-12-29T20:46:58.918Z',
  deleted_at: null,
  name: 'Test brand',
  slug: 'test-brand',
  status: 'disabled',
  brand_profile: {
    created_at: '2020-12-26T20:42:19.931Z',
    about: [ [Object], [Object], [Object], [Object] ],
    cleaned_about: null,
    subtitle: 'subtitle test',
    photo: '1609477287152.jpeg',
    photo_config: { scale: '1.00' },
    id: 1,
    updated_at: '2021-01-01T05:01:27.414Z',
    brand_id: 1,
    brand_page_views: [
      [Object], [Object],
      [Object], [Object],
      [Object], [Object],
      [Object]
    ]
  },
}

如您所见，brand.brand_profile.brand_page_views具有所有对象的列表。现在我只想返回计数，所以我使用以下查询：

const { count, rows } = await Brand.findAndCountAll({
  include: [
      {
        model: BrandProfile,
        as: 'brand_profile',
        include: {
          model: BrandPageView,
          as: 'brand_page_views',
          attributes: [],
        },
      },
    ],
    attributes: {
      include: [
        [
          Sequelize.fn('COUNT', Sequelize.col('brand_profile.brand_page_views.brand_id')),
          'brand_page_views_count',
        ],
      ],
    },
    group: ['brand.id']
})

我收到此错误：

 'missing FROM-clause entry for table "brand"'

它输出的 SQL 是：

SELECT "Brand"."id", "Brand"."created_at", "Brand"."updated_at", "Brand"."deleted_at", "Brand"."name", "Brand"."slug", "Brand"."status", COUNT("brand_profile->brand_page_views"."brand_id") AS "brand_profile.brand_page_views.count", "brand_profile"."created_at" AS "brand_profile.created_at", "brand_profile"."about" AS "brand_profile.about", "brand_profile"."cleaned_about" AS "brand_profile.cleaned_about", "brand_profile"."subtitle" AS "brand_profile.subtitle", "brand_profile"."photo" AS "brand_profile.photo", "brand_profile"."email" AS "brand_profile.email", "brand_profile"."photo_config" AS "brand_profile.photo_config", "brand_profile"."id" AS "brand_profile.id", "brand_profile"."updated_at" AS "brand_profile.updated_at", "brand_profile"."brand_id" AS "brand_profile.brand_id" FROM "brands" AS "Brand" LEFT OUTER JOIN "brand_profile" AS "brand_profile" ON "Br2021-01-05 01:32:26 [sequelize] INFO   Executing (default): SELECT "Brand"."id", "Brand"."created_at", "Brand"."updated_at", "Brand"."deleted_at", "Brand"."name", "Brand"."slug", "Brand"."status", COUNT("brand_profile->brand_page_views"."brand_id") AS "brand_profile.brand_page_views.count", "brand_profile"."created_at" AS "brand_profile.created_at", "brand_profile"."about" AS "brand_profile.about", "brand_profile"."cleaned_about" AS "brand_profile.cleaned_about", "brand_profile"."subtitle" AS "brand_profile.subtitle", "brand_profile"."photo" AS "brand_profile.photo", "brand_profile"."email" AS "brand_profile.email", "brand_profile"."photo_config" AS "brand_profile.photo_config", "brand_profile"."id" AS "brand_profile.id", "brand_profile"."updated_at" AS "brand_profile.updated_at", "brand_profile"."brand_id" AS "brand_profile.brand_id" FROM "brands" AS "Brand" LEFT OUTER JOIN "brand_profile" AS "brand_profile" ON "Brand"."id" = "brand_profile"."brand_id" LEFT OUTER JOIN "brand_page_views" AS "brand_profile->braand"."id" = "brand_profile"."brand_id" LEFT OUTER JOIN "brand_page_views" AS "brand_profile->brand_page_views" ON "brand_profile"."id" = "brand_profile->brand_page_views"."brand_id" WHERE "Brand"."id" = 1 GROUP BY "brand"."id";
nd_page_views" ON "brand_profile"."id" = "brand_profile->brand_page_views"."brand_id" WHERE "Brand"."id" = 1 GROUP BY "brand"."id";

老实说，我已经尝试了很多方法，添加到brand_profile->brand_page_views.brand_id，但无济于事。brand_profile.brand_idgroup

标签： postgresqlsequelize.js

解决方案

Sequelize 并非旨在支持各种 SQL 聚合。因此，在您的情况下，您应该使用sequelize.literal子查询来计算子记录：

attributes: {
      include: [
        [Sequelize.literal('(select COUNT(*) from brand_page_views where brand_page_views.brand_id=brand_profile.id)'),
          'brand_page_views_count'],
      ],
    },

不要忘记删除group: ['brand.id']

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