加入不同外鍵的導軌

Question

我有工作單和僱員表。每臺工單都分配一名員工並分配一名主管。

的workorder.rb有：

belongs_to :super, :class_name => "Employee", :foreign_key => "super_id" 
belongs_to :employee 

我試圖創建一個where子句中使用聯接。它適用於加入:client。但是，:super不起作用。

這是我目前的嘗試：

workorders = workorders.joins(:client,:super).where("wonum like :search or description like :search or clients.client_name like :search or super.employee_full_name like :search ", search: "%#{params[:sSearch]}%") 

我回去：

SELECT COUNT(*) FROM "workorders" INNER JOIN "clients" ON "clients"."id" = "workorders"."client_id" INNER JOIN "employees" ON "employees"."id" = "workorders"."super_id" WHERE (wonum like '%CHUCK%' or description like '%CHUCK%' or clients.client_name like '%CHUCK%' or super.employee_full_name like '%CHUCK%') AND (wostatus_id NOT IN (231,230,9263,9264,232)) 
Completed 500 Internal Server Error in 236ms 
ActiveRecord::StatementInvalid - PG::Error: ERROR: missing FROM-clause entry for table "super" 

感謝您的幫助！

Answer 1

的employees表未被別名爲super，並且不需要在所有在這種情況下使用別名，因爲它是唯一一個加入時間：

workorders = workorders.joins(:client,:super). 
       where("wonum like :search or description like :search or clients.client_name like :search or employees.employee_full_name like :search ", 
       search: "%#{params[:sSearch]}%") 

併爲你的理智的緣故（任何人讀這個），請把這個邏輯變成一個範圍：

scope :search, lambda{ |term| 
    %w(wonum description clients.client_name employees.employee_full_name). 
    map{|field| "#{field} like :search" }. 
    join(" or "), search: term 
} 

workorders = workorders.joins(:client, :super).search("%#{params[:sSearch]}%")