refer: https://stackoverflow.com/questions/14824453/rails-raw-sql-example

搜索怎么在Rails3 使用row sql， 打开上面的链接，可以找到这样的答案，如下图：

sql = "Select * from ... your sql query here"
records_array = ActiveRecord::Base.connection.execute(sql)

可以在接口里使用，例如写：

class YourModel::Controller < ApplicationController
  def test_sqli
    sql = "select * from your_table_name where id = " + params[:my_id] + " or 1 = 1"
    @blogs = ActiveRecord::Base.connection.execute(sql)
  end
end