语法错误mysql（按长度排序）

Question

我得到这个特定的语句的语法错误，我已经真正的声明和检查错误，似乎无法找到任何，也许一双新鲜的眼睛可能会看到的东西。

SELECT Purchase_Order.Airline_Carrier_Code, 
     Aircraft_Purchased.*, 
     Aircraft.Unit_Price * Aircraft_Purchased.Quantity as Total_Cost 
    FROM Aircraft_Purchased 
INNER JOIN Purchase_Order ON Aircraft_Purchased.Order_Number = Purchase_Order.Order_Number 
    INNER JOIN Aircraft_Purchased.Aircraft_ID = Aircraft.Aircraft_ID 
ORDER BY (Purchase_Order.Airline_Carrier_Code), Purchase_Order.Airline_Carrier_Code; 

错误代码我收到低于

1064 - 你在你的SQL语法错误;检查对应于你的MySQL服务器版本使用附近的“.Aircraft_ID ORDER BY长度（Purchase_Order.Airline_Carrier_Code），Purchase_Orde”在行权语法手册* 1 *

Answer 1

你错过了Aircraft第二INNER JOIN后表参考：

SELECT purchase_order.airline_carrier_code, 
     aircraft_purchased.*, 
     aircraft.unit_price * aircraft_purchased.quantity AS Total_Cost 
FROM aircraft_purchased 
     INNER JOIN purchase_order 
       ON aircraft_purchased.order_number = purchase_order.order_number 
     INNER JOIN aircraft <--- here 
       ON aircraft_purchased.aircraft_id = aircraft.aircraft_id 
ORDER BY purchase_order.airline_carrier_code; 

Answer 2

INNER JOIN Aircraft_Purchased.Aircraft_ID = Aircraft.Aircraft_ID ORDER BY

INNER JOIN table name，和ON部分。