在另一个表中查找具有两条特定记录的记录 [英] Finding records with two specific records in another table

问题描述

我有一个 Product 模型，has_and_belongs_to_many :taxons，我想找到特定分类单元中的所有产品.

I have a Product model that has_and_belongs_to_many :taxons, and I want to find all products that are in specific taxons.

例如，如果一个产品同时属于Ruby on Rails"和Shirts"分类群，我希望该产品在数据集中返回，但不如果它只属于其中之一Ruby on Rails"或衬衫"

For example, if a product belongs to both the "Ruby on Rails" and "Shirts" taxon, I want that product to be returned in the dataset, but not if it only belongs to either "Ruby on Rails" or "Shirts"

推荐答案

不久前我遇到了这个问题，幸好有一个很好的解决方案.

I had this problem a while back, thankfully there is a nice solution.

def self.has_taxons(taxons)
  id = arel_table[:id]
  Product.joins(:taxons).where(taxons: { name: taxons }).group(id).having(id.count.eq(taxons.size))
end

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