Question

我确信这很简单，但我无法让它发挥作用。我有以下协会。

model Category
  has_many :category_brands
end

model CategoryBrand
   has_many :category_models
   belongs_to :category
end

model CategoryModel
   has_many :products
   belongs_to :category_brand
end

model Product
   belongs_to :category_model
end

理论上，我想查询所有具有名称等于＆＃34; x＆＃34;的A记录的D记录。像这样：

 @products = Product.joins(category_model: {category_brand: :category}).where("category.name like ?", "%Incline Motors%")

但我不能让这个工作。任何帮助，将不胜感激。

当前错误：

G::UndefinedTable: ERROR: missing FROM-clause entry for table "category" LINE 1: ...es"."id" = "category_brands"."category_id" WHERE (category.n... ^ : SELECT COUNT(*) FROM "products" INNER JOIN "category_models" ON "category_models"."id" = "products"."category_model_id" INNER JOIN "category_brands" ON "category_brands"."id" = "category_models"."category_brand_id" INNER JOIN "categories" ON "categories"."id" = "category_brands"."category_id" WHERE (category.name like '%Incline Motors%')

Answer 1

表名应该是复数 - 请注意SQL语句文本INNER JOIN "categories"

 @products = Product.joins(category_model: {category_brand: :category}).where("categories.name like ?", "%Incline Motors%")

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