Rails管理过滤多选

<%= form_tag products_path, method: :get do %>
  <%= label_tag :color, 'Color:' %>
  <%= select_tag :color, options_for_select(Product.colors.keys.map { |color| [color.humanize, color] }, params[:color]), multiple: true %>

  <%= label_tag :size, 'Size:' %>
  <%= select_tag :size, options_for_select(Product.sizes.keys.map { |size| [size.humanize, size] }, params[:size]), multiple: true %>

  <%= submit_tag 'Filter' %>
<% end %>

class ProductsController < ApplicationController
  def index
    @products = Product.all

    if params[:color].present?
      @products = @products.where(color: params[:color])
    end

    if params[:size].present?
      @products = @products.where(size: params[:size])
    end
  end
end

class Product < ApplicationRecord
  scope :colors, -> { pluck(:color).uniq }
  scope :sizes, -> { pluck(:size).uniq }
end

if params[:color].present?
  @products = @products.where(color: params[:color])
  Rails.logger.debug(@products.to_sql) # 查看生成的SQL
end