将 SQL 查询转换为 Rails ActiveRecord 查询

Question

我有一个 sql 查询，其中有多个可以正常工作的左连接：

query = <<-eos
      select date(t.completed_at) completed_date, s.id district, assignee_id, u.first_name, u.last_name, count(t.id) completed_tasks
      from tasks t
      left join tickets k on k.id = t.ticket_id
      left join installations i on i.id = k.installation_id
      left join administrative_areas a on i.ward_id = a.id
      left join service_areas s on s.id = a.service_district_id
      left join users u on u.id = t.assignee_id
      where 1 = 1
      and s.id = '#{district_id}'
      and t.status = '#{status}'
      and t.kind = 1
      and t.completed_at >= '#{days_ago.days.ago.beginning_of_day.to_s(:db)}'
      and t.completed_at <= '#{days_until.days.ago.beginning_of_day.to_s(:db)}'
      group by date(t.completed_at), s.id, s.name, u.first_name, u.last_name, t.assignee_id
      eos

映射后我得到了这个值：[{:completed_date=>"2015-07-11", :district=>"1339", :assignee_id=>"215371", :assignee_name=>nil, :first_name=>"John_9", :last_name=>"Ant", :completed_tasks=>"1"}] 用于sql 查询。

但我想停止使用 sql 查询并切换到 ActiveRecord 查询，然后我将其转换为 ActiveRecord，如下所示：

Task.joins("LEFT JOIN tickets k ON k.id = tasks.ticket_id").
        joins("LEFT JOIN installations i ON i.id = k.installation_id").
        joins("LEFT JOIN administrative_areas a ON i.ward_id = a.id").
        joins("LEFT JOIN service_areas s ON s.id = a.service_district_id").
        joins("LEFT JOIN users u ON u.id = tasks.assignee_id").
        where(["s.id = ? and tasks.status = ? and tasks.kind = ? and tasks.completed_at >= ? and tasks.completed_at <= ?", 26, "#{status}", 1, "#{days_ago.days.ago.beginning_of_day.to_s(:db)}", "#{days_until.days.ago.beginning_of_day.to_s(:db)}"]).
        select('date(tasks.completed_at) as completed_date, s.id as district, assignee_id, u.first_name, u.last_name, count(tasks.id) as completed_tasks').
        group("date(tasks.completed_at), s.id, s.name, u.first_name, u.last_name, tasks.assignee_id")

但我在这里遇到的问题是尝试从不同表中的多个列中执行select，ActiveRecord 查询返回的唯一值仅属于任务表。不知道哪里做错了，可能是left joins或者select

[#<Task status: 1, assignee_id: 215356, kind: 1>]

请问，如何将上述sql 查询转换为ActiveRecord 查询并获得相同的结果？

Answer 1

您可以使用Scuttle.io 第一个结果总是很糟糕，但尝试在第二个选项卡中配置关联。请尽量避免这样的结构：

where("params.id = #{param[:id]}")

它是不安全的（sql 注入）！