mysql - #1066 - 错误不是唯一的表别名

Question

我正在学习 mysql，我的一个表遇到了问题，它产生了 #1066 - 错误不是唯一的表别名。我尝试了许多不同的查询，但都有相同的结果。有人可以让我摆脱痛苦并帮助指出我做错了什么吗! - 谢谢

表格

looks
---------

look_id(Pk)
user_id
title
description
date_modified

Add_Look_Item
-----------------------

look_id (fk from table 1)
item_id (fk from table 3)

Item
--------------

item_id (pk)
name
details

Add_Images
-------------------
image_id (pk)
item_id (fk from table 3)
image_name

我尝试过的查询 - add_look_item 是复合键

SELECT DISTINCT looks.look_id, looks.title, looks.date_modified, add_look_item.item_id,     add_images.image_name FROM looks JOIN add_look_item ON add_look_item.look_id = looks.look_id
JOIN add_look_item ON add_look_item.item_id = item.item_id WHERE look.user_id = 94

#1066 - error not unique table alias 'add_look_item

SELECT DISTINCT looks.look_id, looks.title, looks.date_modified, add_look_item.item_id,     add_images.image_name FROM looks JOIN 
add_look_item ON add_look_item.looks_id = look.look_id
JOIN add_look_item ON add_look_item.item_id = item.item_id
JOIN add_images ON add_images.item_id = item.item_id WHERE add_look_item.item_id =    item.item_id AND look.user_id = 94

#1066 - error not unique table alias 'add_look_item

SELECT DISTINCT looks.look_id, looks.title, looks.date_modified, add_look_item.item_id,   add_images.image_name FROM looks INNER JOIN add_look_item ON add_look_item.look_id =    look_look_id
INNER JOIN add_images ON add_images.item_id = item.item_id
INNER JOIN add_look_item ON add_look_item.item_id = item.item_id
WHERE look.user_id = 94

#1066 - error not unique table alias 'add_look_item

SELECT DISTINCT looks.look_id, looks.title, looks.date_modified, add_look_item.item_id,    add_images.image_name FROM looks 
INNER JOIN add_look_item ON add_look_item.looks_id = look.look_id
INNER JOIN add_images ON add_images.item_id = item.item_id
INNER JOIN add_look_item ON add_look_item.item_id = item.item_id 
WHERE add_look_item.item_id = item.item_id AND look.user_id = 94


#1066 - error not unique table alias 'add_look_item

SELECT DISTINCT looks.look_id, looks.title, looks.date_modified, add_look_item.item_id,    add_images.image_name FROM looks 
INNER JOIN add_look_item ON add_look_item.looks_id = look.look_id
INNER JOIN add_images ON add_images.item_id = item.item_id
WHERE add_look_item.item_id = item.item_id AND look.user_id = 94

#1054 - Unknown column 'item.item_id' in 'where clause'

谢谢

Answer 1

试试这个 -

SELECT looks.look_id, looks.title, looks.date_modified, add_look_item.item_id, add_images.image_name
FROM looks
JOIN add_look_item
    ON looks.look_id = add_look_item.look_id
JOIN add_images
    ON add_look_item.item_id = add_images.item_id
WHERE look.user_id = 94