如何从自定义 SQL 查询中提取值

Question

我有以下自定义查询，我试图从中提取值，以便它们对我的应用程序有意义

@sizes = Product
                   .joins(:product_properties)
                   .joins('INNER JOIN variant_properties on product_properties.property_id = variant_properties.property_id')
                   .joins('INNER JOIN properties ON properties.id = product_properties.property_id AND properties.id = variant_properties.property_id AND properties.display_name = \'Size\'')
                   .joins('INNER JOIN  variants on variants.product_id = products.id AND variants.id = variant_properties.variant_id')
                   .pluck('products.id as prod_id', 'LEFT(variant_properties.description,1) as short_desc', 'variants.price as price')

下面是我认为的代码

- @sizes.each do |size|
        - size.each do |var|
          = var.price
          = link_to var.short_desc, product, class: 'hollow button tiny'
          %small= number_to_currency(var.price)

问题是我收到一个错误，指出没有固定的数字或没有定义的方法

Answer 1

知道了，pluck 将 return 一个数组的数组，因此您不能像调用方法那样调用它的元素。应该是 size[0], size[1]... 代替.

为了便于使用，我建议您为此构建一个哈希：

@product_sizes = @sizes.each_with_object({}) do |size, result|
  result[size[0]] = {
    'short_desc' => size[1],
    'price' => size[2]
  }
end

然后在你的视图中使用它：

- @products.each_with_index do |product, i|
  .product-list.grid-block
    .small-8.grid-content.text-center
      %h4= product.name.titlecase
      - if size = @product_sizes[product.id]
        = link_to size['short_desc'], product, class: 'hollow button tiny'
        %small= size['price']

祝你好运！

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