mysql - 不唯一的表/别名连接查询

Question

我在 sqlfiddle 中不断收到 Not unique table/alias: 'Donut_Order' 错误我在 stackoverflow 上用谷歌搜索并查看了许多相同的问题，并意识到它与别名有关，但我无法理解它。谁能解释一下我在这里做错了什么？

SELECT date_of_order, Qty_Of_Donuts_In_Order.donut_order_id, Customer.customer_id,
first_name, last_name, street_address, apt_number, city, st, zip_code, home_phone, mobile_phone, other_phone,
qty_of_donuts, Donut.donut_id,
name, description, unit_price,
unit_price * qty_of_donuts AS line_total,
sum(unit_price * qty_of_donuts) AS sub_total,
tax, sum(unit_price * qty_of_donuts) * 1.1 AS total, 
handling_notes
FROM 
Customer JOIN Donut_Order
ON Customer.customer_id = Donut_Order.customer_id,
Donut_Order JOIN Qty_Of_Donuts_In_Order
ON Donut_Order.donut_order_id = Qty_Of_Donuts_In_Order.donut_order_id,
Qty_Of_Donuts_In_Order JOIN Donut
ON Qty_Of_Donuts_In_Order.donut_id = Donut.donut_id;

Answer 1

呃，试试这个:

SELECT date_of_order, qodio.donut_order_id, c.customer_id, first_name, last_name, street_address, apt_number, city, st, zip_code, home_phone, mobile_phone, other_phone, qty_of_donuts, d.donut_id, name, description, unit_price, unit_price * qty_of_donuts AS line_total, sum(unit_price * qty_of_donuts) AS sub_total, tax, sum(unit_price * qty_of_donuts) * 1.1 AS total, handling_notes
FROM Customer c 
JOIN Donut_Order do ON c.customer_id = do.customer_id
JOIN Qty_Of_Donuts_In_Order qodio ON do.donut_order_id = qodio.donut_order_id
JOIN Donut d ON qodio.donut_id = d.donut_id;